{"id":1464,"date":"2020-07-30T21:58:58","date_gmt":"2020-07-30T13:58:58","guid":{"rendered":"https:\/\/www.tansoo.cn\/?p=1464"},"modified":"2020-07-30T21:58:58","modified_gmt":"2020-07-30T13:58:58","slug":"phpbb-39","status":"publish","type":"post","link":"https:\/\/www.tansoo.cn\/?p=1464","title":{"rendered":"100\u9053\u7ec3\u4e60\u5e26\u4f60\u73a9\u8f6cNumpy"},"content":{"rendered":"

Numpy\u662f\u7528Python\u505a\u6570\u636e\u5206\u6790\u6240\u5fc5\u987b\u8981\u638c\u63e1\u7684\u57fa\u7840\u5e93\u4e4b\u4e00\uff0c\u5b83\u53ef\u4ee5\u7528\u6765\u5b58\u50a8\u548c\u5904\u7406\u5927\u578b\u77e9\u9635\uff0c\u5e76\u4e14Numpy\u63d0\u4f9b\u4e86\u8bb8\u591a\u9ad8\u7ea7\u7684\u6570\u503c\u7f16\u7a0b\u5de5\u5177\uff0c\u5982\uff1a\u77e9\u9635\u6570\u636e\u7c7b\u578b\u3001\u77e2\u91cf\u5904\u7406\uff0c\u4ee5\u53ca\u7cbe\u5bc6\u7684\u8fd0\u7b97\u5e93\uff0c\u4e13\u4e3a\u8fdb\u884c\u4e25\u683c\u7684\u6570\u5b57\u5904\u7406\u800c\u4ea7\u751f\u3002<\/p>\n

\u672c\u6587\u5185\u5bb9\u7531\u79d1\u8d5b\u7f51\u7ffb\u8bd1\u6574\u7406\u81eaGithub\u5f00\u6e90\u9879\u76ee(\u90e8\u5206\u9898\u76ee\u4fdd\u7559\u4e86\u539f\u6587\u4f5c\u53c2\u8003)\uff0c\u5efa\u8bae\u8bfb\u8005\u5b8c\u6210\u79d1\u8d5b\u7f51 Numpy\u5feb\u901f\u4e0a\u624b\u6307\u5357 — \u57fa\u7840\u7bc7 \u548c Numpy\u5feb\u901f\u4e0a\u624b\u6307\u5357 — \u8fdb\u9636\u7bc7 \u8fd9\u4e24\u7bc7\u6559\u7a0b\u7684\u5b66\u4e60\u4e4b\u540e\uff0c\u518d\u5bf9\u6b64\u6559\u7a0b\u8fdb\u884c\u8c03\u8bd5\u5b66\u4e60\u3002<\/p>\n

\u4ee5\u4e0b\u4e3a100\u9053Numpy\u4e60\u9898\u53ca\u7b54\u6848<\/p>\n

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Code: <\/strong>[\u5168\u9009]<\/a> [Expand\/Collapse]<\/a><\/div>\n
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    \n
  1. \n
    1<\/span>. \u5bfc\u5165numpy\u5e93\u5e76\u7b80\u5199\u4e3a np<\/div>\n<\/li>\n
  2. \n
     <\/div>\n<\/li>\n
  3. \n
    (<\/span>\u63d0\u793a: import<\/span> \u2026 as<\/span> \u2026)<\/span><\/div>\n<\/li>\n
  4. \n
     <\/div>\n<\/li>\n
  5. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  6. \n
     <\/div>\n<\/li>\n
  7. \n
    # import numpy as np<\/span><\/div>\n<\/li>\n
  8. \n
     <\/div>\n<\/li>\n
  9. \n
    2<\/span>. \u6253\u5370numpy\u7684\u7248\u672c\u548c\u914d\u7f6e\u8bf4\u660e<\/div>\n<\/li>\n
  10. \n
     <\/div>\n<\/li>\n
  11. \n
    (<\/span>\u63d0\u793a: np.__version__,<\/span> np.show_config<\/span>)<\/span><\/div>\n<\/li>\n
  12. \n
     <\/div>\n<\/li>\n
  13. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  14. \n
     <\/div>\n<\/li>\n
  15. \n
    # print(np.__version__)<\/span><\/div>\n<\/li>\n
  16. \n
     <\/div>\n<\/li>\n
  17. \n
    # np.show_config()<\/span><\/div>\n<\/li>\n
  18. \n
     <\/div>\n<\/li>\n
  19. \n
    3<\/span>. \u521b\u5efa\u4e00\u4e2a\u957f\u5ea6\u4e3a10<\/span>\u7684\u7a7a\u5411\u91cf<\/div>\n<\/li>\n
  20. \n
     <\/div>\n<\/li>\n
  21. \n
    (<\/span>\u63d0\u793a: np.zeros<\/span>)<\/span><\/div>\n<\/li>\n
  22. \n
     <\/div>\n<\/li>\n
  23. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  24. \n
     <\/div>\n<\/li>\n
  25. \n
    # Z = np.zeros(10)<\/span><\/div>\n<\/li>\n
  26. \n
     <\/div>\n<\/li>\n
  27. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  28. \n
     <\/div>\n<\/li>\n
  29. \n
    4<\/span>. \u5982\u4f55\u627e\u5230\u4efb\u4f55\u4e00\u4e2a\u6570\u7ec4\u7684\u5185\u5b58\u5927\u5c0f\uff1f<\/div>\n<\/li>\n
  30. \n
     <\/div>\n<\/li>\n
  31. \n
    (<\/span>\u63d0\u793a: size,<\/span> itemsize)<\/span><\/div>\n<\/li>\n
  32. \n
     <\/div>\n<\/li>\n
  33. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  34. \n
     <\/div>\n<\/li>\n
  35. \n
    # Z = np.zeros((10,10))<\/span><\/div>\n<\/li>\n
  36. \n
     <\/div>\n<\/li>\n
  37. \n
    # print("%d bytes" % (Z.size * Z.itemsize))<\/span><\/div>\n<\/li>\n
  38. \n
     <\/div>\n<\/li>\n
  39. \n
    5<\/span>. \u5982\u4f55\u4ece\u547d\u4ee4\u884c\u5f97\u5230numpy\u4e2dadd\u51fd\u6570\u7684\u8bf4\u660e\u6587\u6863?<\/div>\n<\/li>\n
  40. \n
     <\/div>\n<\/li>\n
  41. \n
    (<\/span>\u63d0\u793a: http:\/\/np.info<\/span>)<\/span><\/div>\n<\/li>\n
  42. \n
     <\/div>\n<\/li>\n
  43. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  44. \n
     <\/div>\n<\/li>\n
  45. \n
    # http:\/\/numpy.info(numpy.add)<\/span><\/div>\n<\/li>\n
  46. \n
     <\/div>\n<\/li>\n
  47. \n
    6<\/span>. \u521b\u5efa\u4e00\u4e2a\u957f\u5ea6\u4e3a10<\/span>\u5e76\u4e14\u9664\u4e86\u7b2c\u4e94\u4e2a\u503c\u4e3a1<\/span>\u7684\u7a7a\u5411\u91cf<\/div>\n<\/li>\n
  48. \n
     <\/div>\n<\/li>\n
  49. \n
    (<\/span>\u63d0\u793a: array<\/span>[<\/span>4<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  50. \n
     <\/div>\n<\/li>\n
  51. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  52. \n
     <\/div>\n<\/li>\n
  53. \n
    # Z = np.zeros(10)<\/span><\/div>\n<\/li>\n
  54. \n
     <\/div>\n<\/li>\n
  55. \n
    # Z[4] = 1<\/span><\/div>\n<\/li>\n
  56. \n
     <\/div>\n<\/li>\n
  57. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  58. \n
     <\/div>\n<\/li>\n
  59. \n
    7<\/span>. \u521b\u5efa\u4e00\u4e2a\u503c\u57df\u8303\u56f4\u4ece10<\/span>\u523049<\/span>\u7684\u5411\u91cf<\/div>\n<\/li>\n
  60. \n
     <\/div>\n<\/li>\n
  61. \n
    (<\/span>\u63d0\u793a: np.arange<\/span>)<\/span><\/div>\n<\/li>\n
  62. \n
     <\/div>\n<\/li>\n
  63. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  64. \n
     <\/div>\n<\/li>\n
  65. \n
    # Z = np.arange(10,50)<\/span><\/div>\n<\/li>\n
  66. \n
     <\/div>\n<\/li>\n
  67. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  68. \n
     <\/div>\n<\/li>\n
  69. \n
    8<\/span>. \u53cd\u8f6c\u4e00\u4e2a\u5411\u91cf(<\/span>\u7b2c\u4e00\u4e2a\u5143\u7d20\u53d8\u4e3a\u6700\u540e\u4e00\u4e2a)<\/span><\/div>\n<\/li>\n
  70. \n
     <\/div>\n<\/li>\n
  71. \n
    (<\/span>\u63d0\u793a: array<\/span>[<\/span>::-1<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  72. \n
     <\/div>\n<\/li>\n
  73. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  74. \n
     <\/div>\n<\/li>\n
  75. \n
    # Z = np.arange(50)<\/span><\/div>\n<\/li>\n
  76. \n
     <\/div>\n<\/li>\n
  77. \n
    # Z = Z[::-1]<\/span><\/div>\n<\/li>\n
  78. \n
     <\/div>\n<\/li>\n
  79. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  80. \n
     <\/div>\n<\/li>\n
  81. \n
    9<\/span>. \u521b\u5efa\u4e00\u4e2a 3×3 \u5e76\u4e14\u503c\u4ece0<\/span>\u52308<\/span>\u7684\u77e9\u9635<\/div>\n<\/li>\n
  82. \n
     <\/div>\n<\/li>\n
  83. \n
    (<\/span>\u63d0\u793a: reshape)<\/span><\/div>\n<\/li>\n
  84. \n
     <\/div>\n<\/li>\n
  85. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  86. \n
     <\/div>\n<\/li>\n
  87. \n
    # Z = np.arange(9).reshape(3,3)<\/span><\/div>\n<\/li>\n
  88. \n
     <\/div>\n<\/li>\n
  89. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  90. \n
     <\/div>\n<\/li>\n
  91. \n
    10<\/span>. \u627e\u5230\u6570\u7ec4[<\/span>1<\/span>,<\/span>2<\/span>,<\/span>0<\/span>,<\/span>0<\/span>,<\/span>4<\/span>,<\/span>0<\/span>]<\/span>\u4e2d\u975e0<\/span>\u5143\u7d20\u7684\u4f4d\u7f6e\u7d22\u5f15<\/div>\n<\/li>\n
  92. \n
     <\/div>\n<\/li>\n
  93. \n
    (<\/span>\u63d0\u793a: np.nonzero<\/span>)<\/span><\/div>\n<\/li>\n
  94. \n
     <\/div>\n<\/li>\n
  95. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  96. \n
     <\/div>\n<\/li>\n
  97. \n
    # nz = np.nonzero([1,2,0,0,4,0])<\/span><\/div>\n<\/li>\n
  98. \n
     <\/div>\n<\/li>\n
  99. \n
    # print(nz)<\/span><\/div>\n<\/li>\n
  100. \n
     <\/div>\n<\/li>\n
  101. \n
    11<\/span>. \u521b\u5efa\u4e00\u4e2a 3×3 \u7684\u5355\u4f4d\u77e9\u9635<\/div>\n<\/li>\n
  102. \n
     <\/div>\n<\/li>\n
  103. \n
    (<\/span>\u63d0\u793a: np.eye<\/span>)<\/span><\/div>\n<\/li>\n
  104. \n
     <\/div>\n<\/li>\n
  105. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  106. \n
     <\/div>\n<\/li>\n
  107. \n
    # Z = np.eye(3)<\/span><\/div>\n<\/li>\n
  108. \n
     <\/div>\n<\/li>\n
  109. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  110. \n
     <\/div>\n<\/li>\n
  111. \n
    12<\/span>. \u521b\u5efa\u4e00\u4e2a 3x3x3\u7684\u968f\u673a\u6570\u7ec4<\/div>\n<\/li>\n
  112. \n
     <\/div>\n<\/li>\n
  113. \n
    (<\/span>\u63d0\u793a: np.random<\/span>.random<\/span>)<\/span><\/div>\n<\/li>\n
  114. \n
     <\/div>\n<\/li>\n
  115. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  116. \n
     <\/div>\n<\/li>\n
  117. \n
    # Z = np.random.random((3,3,3))<\/span><\/div>\n<\/li>\n
  118. \n
     <\/div>\n<\/li>\n
  119. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  120. \n
     <\/div>\n<\/li>\n
  121. \n
    13<\/span>. \u521b\u5efa\u4e00\u4e2a 10×10 \u7684\u968f\u673a\u6570\u7ec4\u5e76\u627e\u5230\u5b83\u7684\u6700\u5927\u503c\u548c\u6700\u5c0f\u503c<\/div>\n<\/li>\n
  122. \n
     <\/div>\n<\/li>\n
  123. \n
    (<\/span>\u63d0\u793a: min<\/span>,<\/span> max<\/span>)<\/span><\/div>\n<\/li>\n
  124. \n
     <\/div>\n<\/li>\n
  125. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  126. \n
     <\/div>\n<\/li>\n
  127. \n
    # Z = np.random.random((10,10))<\/span><\/div>\n<\/li>\n
  128. \n
     <\/div>\n<\/li>\n
  129. \n
    # Zmin, Zmax = Z.min(), Z.max()<\/span><\/div>\n<\/li>\n
  130. \n
     <\/div>\n<\/li>\n
  131. \n
    # print(Zmin, Zmax)<\/span><\/div>\n<\/li>\n
  132. \n
     <\/div>\n<\/li>\n
  133. \n
    14<\/span>. \u521b\u5efa\u4e00\u4e2a\u957f\u5ea6\u4e3a30<\/span>\u7684\u968f\u673a\u5411\u91cf\u5e76\u627e\u5230\u5b83\u7684\u5e73\u5747\u503c<\/div>\n<\/li>\n
  134. \n
     <\/div>\n<\/li>\n
  135. \n
    (<\/span>\u63d0\u793a: mean)<\/span><\/div>\n<\/li>\n
  136. \n
     <\/div>\n<\/li>\n
  137. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  138. \n
     <\/div>\n<\/li>\n
  139. \n
    # Z = np.random.random(30)<\/span><\/div>\n<\/li>\n
  140. \n
     <\/div>\n<\/li>\n
  141. \n
    # m = Z.mean()<\/span><\/div>\n<\/li>\n
  142. \n
     <\/div>\n<\/li>\n
  143. \n
    # print(m)<\/span><\/div>\n<\/li>\n
  144. \n
     <\/div>\n<\/li>\n
  145. \n
    15<\/span>.\u521b\u5efa\u4e00\u4e8c\u7ef4\u6570\u7ec4\uff0c\u5176\u4e2d\u8fb9\u754c\u503c\u4e3a1<\/span>\uff0c\u5176\u4f59\u503c\u4e3a0<\/span><\/div>\n<\/li>\n
  146. \n
     <\/div>\n<\/li>\n
  147. \n
    (<\/span>\u63d0\u793a: array<\/span>[<\/span>1<\/span>:-1<\/span>,<\/span> 1<\/span>:-1<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  148. \n
     <\/div>\n<\/li>\n
  149. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  150. \n
     <\/div>\n<\/li>\n
  151. \n
    # Z = np.ones((10,10))<\/span><\/div>\n<\/li>\n
  152. \n
     <\/div>\n<\/li>\n
  153. \n
    # Z[1:-1,1:-1] = 0<\/span><\/div>\n<\/li>\n
  154. \n
     <\/div>\n<\/li>\n
  155. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  156. \n
     <\/div>\n<\/li>\n
  157. \n
    16<\/span>. \u5bf9\u4e8e\u4e00\u4e2a\u5b58\u5728\u5728\u6570\u7ec4\uff0c\u5982\u4f55\u6dfb\u52a0\u4e00\u4e2a\u75280<\/span>\u586b\u5145\u7684\u8fb9\u754c?<\/div>\n<\/li>\n
  158. \n
     <\/div>\n<\/li>\n
  159. \n
    (<\/span>\u63d0\u793a: np.pad<\/span>)<\/span><\/div>\n<\/li>\n
  160. \n
     <\/div>\n<\/li>\n
  161. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  162. \n
     <\/div>\n<\/li>\n
  163. \n
    # Z = np.ones((5,5))<\/span><\/div>\n<\/li>\n
  164. \n
     <\/div>\n<\/li>\n
  165. \n
    # Z = np.pad(Z, pad_width=1, mode=’constant’, constant_values=0)<\/span><\/div>\n<\/li>\n
  166. \n
     <\/div>\n<\/li>\n
  167. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  168. \n
     <\/div>\n<\/li>\n
  169. \n
    17<\/span>. \u4ee5\u4e0b\u8868\u8fbe\u5f0f\u8fd0\u884c\u7684\u7ed3\u679c\u5206\u522b\u662f\u4ec0\u4e48?<\/div>\n<\/li>\n
  170. \n
     <\/div>\n<\/li>\n
  171. \n
    (<\/span>\u63d0\u793a: NaN =<\/span> not<\/span> a number,<\/span> inf =<\/span> infinity)<\/span><\/div>\n<\/li>\n
  172. \n
     <\/div>\n<\/li>\n
  173. \n
    0<\/span>*np.nan<\/span><\/div>\n<\/li>\n
  174. \n
     <\/div>\n<\/li>\n
  175. \n
    np.nan<\/span>==<\/span>np.nan<\/span><\/div>\n<\/li>\n
  176. \n
     <\/div>\n<\/li>\n
  177. \n
    np.inf<\/span>><\/span>np.nan<\/span><\/div>\n<\/li>\n
  178. \n
     <\/div>\n<\/li>\n
  179. \n
    np.nan<\/span>-np.nan<\/span><\/div>\n<\/li>\n
  180. \n
     <\/div>\n<\/li>\n
  181. \n
    0.3<\/span>==<\/span>3<\/span>*0.1<\/span><\/div>\n<\/li>\n
  182. \n
     <\/div>\n<\/li>\n
  183. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  184. \n
     <\/div>\n<\/li>\n
  185. \n
    # print(0 * np.nan)<\/span><\/div>\n<\/li>\n
  186. \n
     <\/div>\n<\/li>\n
  187. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  188. \n
     <\/div>\n<\/li>\n
  189. \n
    # print(np.nan == np.nan)<\/span><\/div>\n<\/li>\n
  190. \n
     <\/div>\n<\/li>\n
  191. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  192. \n
     <\/div>\n<\/li>\n
  193. \n
    # print(np.inf > np.nan)<\/span><\/div>\n<\/li>\n
  194. \n
     <\/div>\n<\/li>\n
  195. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  196. \n
     <\/div>\n<\/li>\n
  197. \n
    # print(np.nan – np.nan)<\/span><\/div>\n<\/li>\n
  198. \n
     <\/div>\n<\/li>\n
  199. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  200. \n
     <\/div>\n<\/li>\n
  201. \n
    # print(0.3 == 3 * 0.1)<\/span><\/div>\n<\/li>\n
  202. \n
     <\/div>\n<\/li>\n
  203. \n
    18<\/span>. \u521b\u5efa\u4e00\u4e2a 5×5\u7684\u77e9\u9635\uff0c\u5e76\u8bbe\u7f6e\u503c1<\/span>,<\/span>2<\/span>,<\/span>3<\/span>,<\/span>4<\/span>\u843d\u5728\u5176\u5bf9\u89d2\u7ebf\u4e0b\u65b9\u4f4d\u7f6e<\/div>\n<\/li>\n
  204. \n
     <\/div>\n<\/li>\n
  205. \n
    (<\/span>\u63d0\u793a: np.diag<\/span>)<\/span><\/div>\n<\/li>\n
  206. \n
     <\/div>\n<\/li>\n
  207. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  208. \n
     <\/div>\n<\/li>\n
  209. \n
    # Z = np.diag(1+np.arange(4),k=-1)<\/span><\/div>\n<\/li>\n
  210. \n
     <\/div>\n<\/li>\n
  211. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  212. \n
     <\/div>\n<\/li>\n
  213. \n
    19<\/span>. \u521b\u5efa\u4e00\u4e2a8×8 \u7684\u77e9\u9635\uff0c\u5e76\u4e14\u8bbe\u7f6e\u6210\u68cb\u76d8\u6837\u5f0f<\/div>\n<\/li>\n
  214. \n
     <\/div>\n<\/li>\n
  215. \n
    (<\/span>\u63d0\u793a: array<\/span>[<\/span>::2<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  216. \n
     <\/div>\n<\/li>\n
  217. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  218. \n
     <\/div>\n<\/li>\n
  219. \n
    # Z = np.zeros((8,8),dtype=int)<\/span><\/div>\n<\/li>\n
  220. \n
     <\/div>\n<\/li>\n
  221. \n
    #Z[1::2,::2] = 1<\/span><\/div>\n<\/li>\n
  222. \n
     <\/div>\n<\/li>\n
  223. \n
    # Z[::2,1::2] = 1<\/span><\/div>\n<\/li>\n
  224. \n
     <\/div>\n<\/li>\n
  225. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  226. \n
     <\/div>\n<\/li>\n
  227. \n
    20<\/span>. \u8003\u8651\u4e00\u4e2a (<\/span>6<\/span>,<\/span>7<\/span>,<\/span>8<\/span>)<\/span> \u5f62\u72b6\u7684\u6570\u7ec4\uff0c\u5176\u7b2c100<\/span>\u4e2a\u5143\u7d20\u7684\u7d22\u5f15(<\/span>x,<\/span>y,<\/span>z)<\/span>\u662f\u4ec0\u4e48?<\/div>\n<\/li>\n
  228. \n
     <\/div>\n<\/li>\n
  229. \n
    (<\/span>\u63d0\u793a: np.unravel_index<\/span>)<\/span><\/div>\n<\/li>\n
  230. \n
     <\/div>\n<\/li>\n
  231. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  232. \n
     <\/div>\n<\/li>\n
  233. \n
    # print(np.unravel_index(100,(6,7,8)))<\/span><\/div>\n<\/li>\n
  234. \n
     <\/div>\n<\/li>\n
  235. \n
    21<\/span>. \u7528tile\u51fd\u6570\u53bb\u521b\u5efa\u4e00\u4e2a 8×8\u7684\u68cb\u76d8\u6837\u5f0f\u77e9\u9635<\/div>\n<\/li>\n
  236. \n
     <\/div>\n<\/li>\n
  237. \n
    (<\/span>\u63d0\u793a: np.tile<\/span>)<\/span><\/div>\n<\/li>\n
  238. \n
     <\/div>\n<\/li>\n
  239. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  240. \n
     <\/div>\n<\/li>\n
  241. \n
    # Z = np.tile( np.array([[0,1],[1,0]]), (4,4))<\/span><\/div>\n<\/li>\n
  242. \n
     <\/div>\n<\/li>\n
  243. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  244. \n
     <\/div>\n<\/li>\n
  245. \n
    22<\/span>. \u5bf9\u4e00\u4e2a5×5\u7684\u968f\u673a\u77e9\u9635\u505a\u5f52\u4e00\u5316<\/div>\n<\/li>\n
  246. \n
     <\/div>\n<\/li>\n
  247. \n
    (<\/span>\u63d0\u793a: (<\/span>x – min<\/span>)<\/span> \/ (<\/span>max<\/span> – min<\/span>)<\/span>)<\/span><\/div>\n<\/li>\n
  248. \n
     <\/div>\n<\/li>\n
  249. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  250. \n
     <\/div>\n<\/li>\n
  251. \n
    # Z = np.random.random((5,5))<\/span><\/div>\n<\/li>\n
  252. \n
     <\/div>\n<\/li>\n
  253. \n
    # Zmax, Zmin = Z.max(), Z.min()<\/span><\/div>\n<\/li>\n
  254. \n
     <\/div>\n<\/li>\n
  255. \n
    # Z = (Z – Zmin)\/(Zmax – Zmin)<\/span><\/div>\n<\/li>\n
  256. \n
     <\/div>\n<\/li>\n
  257. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  258. \n
     <\/div>\n<\/li>\n
  259. \n
    23<\/span>. \u521b\u5efa\u4e00\u4e2a\u5c06\u989c\u8272\u63cf\u8ff0\u4e3a(<\/span>RGBA)<\/span>\u56db\u4e2a\u65e0\u7b26\u53f7\u5b57\u8282\u7684\u81ea\u5b9a\u4e49dtype\uff1f<\/div>\n<\/li>\n
  260. \n
     <\/div>\n<\/li>\n
  261. \n
    (<\/span>\u63d0\u793a: np.dtype<\/span>)<\/span><\/div>\n<\/li>\n
  262. \n
     <\/div>\n<\/li>\n
  263. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  264. \n
     <\/div>\n<\/li>\n
  265. \n
    # color = np.dtype([("r", np.ubyte, 1),<\/span><\/div>\n<\/li>\n
  266. \n
     <\/div>\n<\/li>\n
  267. \n
    # ("g", np.ubyte, 1),<\/span><\/div>\n<\/li>\n
  268. \n
     <\/div>\n<\/li>\n
  269. \n
    # ("b", np.ubyte, 1),<\/span><\/div>\n<\/li>\n
  270. \n
     <\/div>\n<\/li>\n
  271. \n
    # ("a", np.ubyte, 1)])<\/span><\/div>\n<\/li>\n
  272. \n
     <\/div>\n<\/li>\n
  273. \n
    # color<\/span><\/div>\n<\/li>\n
  274. \n
     <\/div>\n<\/li>\n
  275. \n
    24<\/span>. \u4e00\u4e2a5×3\u7684\u77e9\u9635\u4e0e\u4e00\u4e2a3×2\u7684\u77e9\u9635\u76f8\u4e58\uff0c\u5b9e\u77e9\u9635\u4e58\u79ef\u662f\u4ec0\u4e48\uff1f<\/div>\n<\/li>\n
  276. \n
     <\/div>\n<\/li>\n
  277. \n
    (<\/span>\u63d0\u793a: np.dot<\/span> | @<\/span>)<\/span><\/div>\n<\/li>\n
  278. \n
     <\/div>\n<\/li>\n
  279. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  280. \n
     <\/div>\n<\/li>\n
  281. \n
    # Z = np.dot(np.ones((5,3)), np.ones((3,2)))<\/span><\/div>\n<\/li>\n
  282. \n
     <\/div>\n<\/li>\n
  283. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  284. \n
     <\/div>\n<\/li>\n
  285. \n
    25<\/span>. \u7ed9\u5b9a\u4e00\u4e2a\u4e00\u7ef4\u6570\u7ec4\uff0c\u5bf9\u5176\u57283<\/span>\u52308<\/span>\u4e4b\u95f4\u7684\u6240\u6709\u5143\u7d20\u53d6\u53cd<\/div>\n<\/li>\n
  286. \n
     <\/div>\n<\/li>\n
  287. \n
    (<\/span>\u63d0\u793a: >,<\/span> <=<\/span>)<\/span><\/div>\n<\/li>\n
  288. \n
     <\/div>\n<\/li>\n
  289. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  290. \n
     <\/div>\n<\/li>\n
  291. \n
    # Z = np.arange(11)<\/span><\/div>\n<\/li>\n
  292. \n
     <\/div>\n<\/li>\n
  293. \n
    # Z[(3 < Z) & (Z <= 8)] *= -1<\/span><\/div>\n<\/li>\n
  294. \n
     <\/div>\n<\/li>\n
  295. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  296. \n
     <\/div>\n<\/li>\n
  297. \n
    26<\/span>. \u4e0b\u9762\u811a\u672c\u8fd0\u884c\u540e\u7684\u7ed3\u679c\u662f\u4ec0\u4e48?<\/div>\n<\/li>\n
  298. \n
     <\/div>\n<\/li>\n
  299. \n
    (<\/span>\u63d0\u793a: np.sum<\/span>)<\/span><\/div>\n<\/li>\n
  300. \n
     <\/div>\n<\/li>\n
  301. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  302. \n
     <\/div>\n<\/li>\n
  303. \n
    # print(sum(range(5),-1))<\/span><\/div>\n<\/li>\n
  304. \n
     <\/div>\n<\/li>\n
  305. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  306. \n
     <\/div>\n<\/li>\n
  307. \n
    # from numpy import *<\/span><\/div>\n<\/li>\n
  308. \n
     <\/div>\n<\/li>\n
  309. \n
    # print(sum(range(5),-1))<\/span><\/div>\n<\/li>\n
  310. \n
     <\/div>\n<\/li>\n
  311. \n
    27<\/span>. \u8003\u8651\u4e00\u4e2a\u6574\u6570\u5411\u91cfZ,<\/span>\u4e0b\u5217\u8868\u8fbe\u5408\u6cd5\u7684\u662f\u54ea\u4e2a?<\/div>\n<\/li>\n
  312. \n
     <\/div>\n<\/li>\n
  313. \n
    Z**Z<\/div>\n<\/li>\n
  314. \n
     <\/div>\n<\/li>\n
  315. \n
    2<\/span><<<\/span>Z>><\/span>2<\/span><\/div>\n<\/li>\n
  316. \n
     <\/div>\n<\/li>\n
  317. \n
    Z<<\/span>-Z<\/div>\n<\/li>\n
  318. \n
     <\/div>\n<\/li>\n
  319. \n
    1j*Z<\/div>\n<\/li>\n
  320. \n
     <\/div>\n<\/li>\n
  321. \n
    Z\/1<\/span>\/1<\/span><\/div>\n<\/li>\n
  322. \n
     <\/div>\n<\/li>\n
  323. \n
    Z<<\/span>Z><\/span>Z<\/div>\n<\/li>\n
  324. \n
     <\/div>\n<\/li>\n
  325. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  326. \n
     <\/div>\n<\/li>\n
  327. \n
    # Z = np.arange(5)<\/span><\/div>\n<\/li>\n
  328. \n
     <\/div>\n<\/li>\n
  329. \n
    # Z ** Z # legal<\/span><\/div>\n<\/li>\n
  330. \n
     <\/div>\n<\/li>\n
  331. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  332. \n
     <\/div>\n<\/li>\n
  333. \n
    # Z = np.arange(5)<\/span><\/div>\n<\/li>\n
  334. \n
     <\/div>\n<\/li>\n
  335. \n
    # 2 << Z >> 2 # false<\/span><\/div>\n<\/li>\n
  336. \n
     <\/div>\n<\/li>\n
  337. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  338. \n
     <\/div>\n<\/li>\n
  339. \n
    # Z = np.arange(5)<\/span><\/div>\n<\/li>\n
  340. \n
     <\/div>\n<\/li>\n
  341. \n
    # Z <- Z # legal<\/span><\/div>\n<\/li>\n
  342. \n
     <\/div>\n<\/li>\n
  343. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  344. \n
     <\/div>\n<\/li>\n
  345. \n
    # Z = np.arange(5)<\/span><\/div>\n<\/li>\n
  346. \n
     <\/div>\n<\/li>\n
  347. \n
    # 1j*Z # legal<\/span><\/div>\n<\/li>\n
  348. \n
     <\/div>\n<\/li>\n
  349. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  350. \n
     <\/div>\n<\/li>\n
  351. \n
    # Z = np.arange(5)<\/span><\/div>\n<\/li>\n
  352. \n
     <\/div>\n<\/li>\n
  353. \n
    # Z\/1\/1 # legal<\/span><\/div>\n<\/li>\n
  354. \n
     <\/div>\n<\/li>\n
  355. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  356. \n
     <\/div>\n<\/li>\n
  357. \n
    # Z = np.arange(5)<\/span><\/div>\n<\/li>\n
  358. \n
     <\/div>\n<\/li>\n
  359. \n
    # Z<Z>Z # false<\/span><\/div>\n<\/li>\n
  360. \n
     <\/div>\n<\/li>\n
  361. \n
    28<\/span>. \u4e0b\u5217\u8868\u8fbe\u5f0f\u7684\u7ed3\u679c\u5206\u522b\u662f\u4ec0\u4e48?<\/div>\n<\/li>\n
  362. \n
     <\/div>\n<\/li>\n
  363. \n
    np.array<\/span>(<\/span>0<\/span>)<\/span> \/np.array<\/span>(<\/span>0<\/span>)<\/span><\/div>\n<\/li>\n
  364. \n
     <\/div>\n<\/li>\n
  365. \n
    np.array<\/span>(<\/span>0<\/span>)<\/span> \/\/np.array<\/span>(<\/span>0<\/span>)<\/span><\/div>\n<\/li>\n
  366. \n
     <\/div>\n<\/li>\n
  367. \n
    np.array<\/span>(<\/span>[<\/span>np.nan<\/span>]<\/span>)<\/span>.astype<\/span>(<\/span>int<\/span>)<\/span>.astype<\/span>(<\/span>float<\/span>)<\/span><\/div>\n<\/li>\n
  368. \n
     <\/div>\n<\/li>\n
  369. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  370. \n
     <\/div>\n<\/li>\n
  371. \n
    # print(np.array(0) \/ np.array(0))<\/span><\/div>\n<\/li>\n
  372. \n
     <\/div>\n<\/li>\n
  373. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  374. \n
     <\/div>\n<\/li>\n
  375. \n
    # print(np.array(0) \/\/ np.array(0))<\/span><\/div>\n<\/li>\n
  376. \n
     <\/div>\n<\/li>\n
  377. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  378. \n
     <\/div>\n<\/li>\n
  379. \n
    # print(np.array([np.nan]).astype(int).astype(float))<\/span><\/div>\n<\/li>\n
  380. \n
     <\/div>\n<\/li>\n
  381. \n
    29<\/span>. \u5982\u4f55\u4ece\u96f6\u4f4d\u5bf9\u6d6e\u70b9\u6570\u7ec4\u505a\u820d\u5165 ?<\/div>\n<\/li>\n
  382. \n
     <\/div>\n<\/li>\n
  383. \n
    (<\/span>\u63d0\u793a: np.uniform<\/span>,<\/span> np.copysign<\/span>,<\/span> np.ceil<\/span>,<\/span> np.abs<\/span>)<\/span><\/div>\n<\/li>\n
  384. \n
     <\/div>\n<\/li>\n
  385. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  386. \n
     <\/div>\n<\/li>\n
  387. \n
    # Z = np.random.uniform(-10,+10,10)<\/span><\/div>\n<\/li>\n
  388. \n
     <\/div>\n<\/li>\n
  389. \n
    # print (np.copysign(np.ceil(np.abs(Z)), Z))<\/span><\/div>\n<\/li>\n
  390. \n
     <\/div>\n<\/li>\n
  391. \n
    30<\/span>. \u5982\u4f55\u627e\u5230\u4e24\u4e2a\u6570\u7ec4\u4e2d\u7684\u5171\u540c\u5143\u7d20?<\/div>\n<\/li>\n
  392. \n
     <\/div>\n<\/li>\n
  393. \n
    (<\/span>\u63d0\u793a: np.intersect1d<\/span>)<\/span><\/div>\n<\/li>\n
  394. \n
     <\/div>\n<\/li>\n
  395. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  396. \n
     <\/div>\n<\/li>\n
  397. \n
    # Z1 = np.random.randint(0,10,10)<\/span><\/div>\n<\/li>\n
  398. \n
     <\/div>\n<\/li>\n
  399. \n
    # Z2 = np.random.randint(0,10,10)<\/span><\/div>\n<\/li>\n
  400. \n
     <\/div>\n<\/li>\n
  401. \n
    # print(np.intersect1d(Z1,Z2))<\/span><\/div>\n<\/li>\n
  402. \n
     <\/div>\n<\/li>\n
  403. \n
    31<\/span>. \u5982\u4f55\u5ffd\u7565\u6240\u6709\u7684 numpy \u8b66\u544a(<\/span>\u5c3d\u7ba1\u4e0d\u5efa\u8bae\u8fd9\u4e48\u505a)<\/span>?<\/div>\n<\/li>\n
  404. \n
     <\/div>\n<\/li>\n
  405. \n
    (<\/span>\u63d0\u793a: np.seterr<\/span>,<\/span> np.errstate<\/span>)<\/span><\/div>\n<\/li>\n
  406. \n
     <\/div>\n<\/li>\n
  407. \n
    # Suicide mode on<\/span><\/div>\n<\/li>\n
  408. \n
     <\/div>\n<\/li>\n
  409. \n
    defaults=<\/span>np.seterr<\/span>(<\/span>all<\/span>=<\/span>"ignore"<\/span>)<\/span><\/div>\n<\/li>\n
  410. \n
     <\/div>\n<\/li>\n
  411. \n
    Z=<\/span>np.ones<\/span>(<\/span>1<\/span>)<\/span> \/0<\/span><\/div>\n<\/li>\n
  412. \n
     <\/div>\n<\/li>\n
  413. \n
    # Back to sanity<\/span><\/div>\n<\/li>\n
  414. \n
     <\/div>\n<\/li>\n
  415. \n
    _=<\/span>np.seterr<\/span>(<\/span>**defaults)<\/span><\/div>\n<\/li>\n
  416. \n
     <\/div>\n<\/li>\n
  417. \n
    Anequivalentway,<\/span> withacontextmanager:<\/div>\n<\/li>\n
  418. \n
     <\/div>\n<\/li>\n
  419. \n
    withnp.errstate<\/span>(<\/span>divide=<\/span>‘ignore’<\/span>)<\/span>:<\/div>\n<\/li>\n
  420. \n
     <\/div>\n<\/li>\n
  421. \n
    Z=<\/span>np.ones<\/span>(<\/span>1<\/span>)<\/span> \/0<\/span><\/div>\n<\/li>\n
  422. \n
     <\/div>\n<\/li>\n
  423. \n
    32<\/span>. \u4e0b\u9762\u7684\u8868\u8fbe\u5f0f\u662f\u6b63\u786e\u7684\u5417?<\/div>\n<\/li>\n
  424. \n
     <\/div>\n<\/li>\n
  425. \n
    (<\/span>\u63d0\u793a: imaginary number)<\/span><\/div>\n<\/li>\n
  426. \n
     <\/div>\n<\/li>\n
  427. \n
    np.sqrt<\/span>(<\/span>–1<\/span>)<\/span> ==<\/span>np.emath<\/span>.sqrt<\/span>(<\/span>–1<\/span>)<\/span><\/div>\n<\/li>\n
  428. \n
     <\/div>\n<\/li>\n
  429. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  430. \n
     <\/div>\n<\/li>\n
  431. \n
    # np.sqrt(-1) == np.emath.sqrt(-1) # False<\/span><\/div>\n<\/li>\n
  432. \n
     <\/div>\n<\/li>\n
  433. \n
    33<\/span>. \u5982\u4f55\u5f97\u5230\u6628\u5929\uff0c\u4eca\u5929\uff0c\u660e\u5929\u7684\u65e5\u671f?<\/div>\n<\/li>\n
  434. \n
     <\/div>\n<\/li>\n
  435. \n
    (<\/span>\u63d0\u793a: np.datetime64<\/span>,<\/span> np.timedelta64<\/span>)<\/span><\/div>\n<\/li>\n
  436. \n
     <\/div>\n<\/li>\n
  437. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  438. \n
     <\/div>\n<\/li>\n
  439. \n
    # yesterday = np.datetime64(‘today’, ‘D’) – np.timedelta64(1, ‘D’)<\/span><\/div>\n<\/li>\n
  440. \n
     <\/div>\n<\/li>\n
  441. \n
    # today = np.datetime64(‘today’, ‘D’)<\/span><\/div>\n<\/li>\n
  442. \n
     <\/div>\n<\/li>\n
  443. \n
    # tomorrow = np.datetime64(‘today’, ‘D’) + np.timedelta64(1, ‘D’)<\/span><\/div>\n<\/li>\n
  444. \n
     <\/div>\n<\/li>\n
  445. \n
    # print ("Yesterday is " + str(yesterday))<\/span><\/div>\n<\/li>\n
  446. \n
     <\/div>\n<\/li>\n
  447. \n
    # print ("Today is " + str(today))<\/span><\/div>\n<\/li>\n
  448. \n
     <\/div>\n<\/li>\n
  449. \n
    # print ("Tomorrow is "+ str(tomorrow))<\/span><\/div>\n<\/li>\n
  450. \n
     <\/div>\n<\/li>\n
  451. \n
    34<\/span>. \u5982\u4f55\u5f97\u5230\u6240\u6709\u4e0e2016<\/span>\u5e747<\/span>\u6708\u5bf9\u5e94\u7684\u65e5\u671f\uff1f<\/div>\n<\/li>\n
  452. \n
     <\/div>\n<\/li>\n
  453. \n
    (<\/span>\u63d0\u793a: np.arange<\/span>(<\/span>dtype=<\/span>datetime64[<\/span>‘D’<\/span>]<\/span>)<\/span>)<\/span><\/div>\n<\/li>\n
  454. \n
     <\/div>\n<\/li>\n
  455. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  456. \n
     <\/div>\n<\/li>\n
  457. \n
    # Z = np.arange(‘2016-07’, ‘2016-08′, dtype=’datetime64[D]’)<\/span><\/div>\n<\/li>\n
  458. \n
     <\/div>\n<\/li>\n
  459. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  460. \n
     <\/div>\n<\/li>\n
  461. \n
    35<\/span>. \u5982\u4f55\u76f4\u63a5\u5728\u4f4d\u8ba1\u7b97(<\/span>A+B)<\/span>\\*(<\/span>-A\/2<\/span>)<\/span>(<\/span>\u4e0d\u5efa\u7acb\u526f\u672c)<\/span>?<\/div>\n<\/li>\n
  462. \n
     <\/div>\n<\/li>\n
  463. \n
    (<\/span>\u63d0\u793a: np.add<\/span>(<\/span>out=<\/span>)<\/span>,<\/span> np.negative<\/span>(<\/span>out=<\/span>)<\/span>,<\/span> np.multiply<\/span>(<\/span>out=<\/span>)<\/span>,<\/span> np.divide<\/span>(<\/span>out=<\/span>)<\/span>)<\/span><\/div>\n<\/li>\n
  464. \n
     <\/div>\n<\/li>\n
  465. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  466. \n
     <\/div>\n<\/li>\n
  467. \n
    # A = np.ones(3)*1<\/span><\/div>\n<\/li>\n
  468. \n
     <\/div>\n<\/li>\n
  469. \n
    # B = np.ones(3)*2<\/span><\/div>\n<\/li>\n
  470. \n
     <\/div>\n<\/li>\n
  471. \n
    # C = np.ones(3)*3<\/span><\/div>\n<\/li>\n
  472. \n
     <\/div>\n<\/li>\n
  473. \n
    # np.add(A,B,out=B)<\/span><\/div>\n<\/li>\n
  474. \n
     <\/div>\n<\/li>\n
  475. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  476. \n
     <\/div>\n<\/li>\n
  477. \n
    # np.divide(A,2,out=A)<\/span><\/div>\n<\/li>\n
  478. \n
     <\/div>\n<\/li>\n
  479. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  480. \n
     <\/div>\n<\/li>\n
  481. \n
    # np.negative(A,out=A)<\/span><\/div>\n<\/li>\n
  482. \n
     <\/div>\n<\/li>\n
  483. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  484. \n
     <\/div>\n<\/li>\n
  485. \n
    # np.multiply(A,B,out=A)<\/span><\/div>\n<\/li>\n
  486. \n
     <\/div>\n<\/li>\n
  487. \n
    36<\/span>. \u7528\u4e94\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\u53bb\u63d0\u53d6\u4e00\u4e2a\u968f\u673a\u6570\u7ec4\u7684\u6574\u6570\u90e8\u5206<\/div>\n<\/li>\n
  488. \n
     <\/div>\n<\/li>\n
  489. \n
    (<\/span>\u63d0\u793a: %,<\/span> np.floor<\/span>,<\/span> np.ceil<\/span>,<\/span> astype,<\/span> np.trunc<\/span>)<\/span><\/div>\n<\/li>\n
  490. \n
     <\/div>\n<\/li>\n
  491. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  492. \n
     <\/div>\n<\/li>\n
  493. \n
    # Z = np.random.uniform(0,10,10)<\/span><\/div>\n<\/li>\n
  494. \n
     <\/div>\n<\/li>\n
  495. \n
    # print (Z – Z%1)<\/span><\/div>\n<\/li>\n
  496. \n
     <\/div>\n<\/li>\n
  497. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  498. \n
     <\/div>\n<\/li>\n
  499. \n
    # print (np.floor(Z))<\/span><\/div>\n<\/li>\n
  500. \n
     <\/div>\n<\/li>\n
  501. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  502. \n
     <\/div>\n<\/li>\n
  503. \n
    # print (np.ceil(Z)-1)<\/span><\/div>\n<\/li>\n
  504. \n
     <\/div>\n<\/li>\n
  505. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  506. \n
     <\/div>\n<\/li>\n
  507. \n
    # print (Z.astype(int))<\/span><\/div>\n<\/li>\n
  508. \n
     <\/div>\n<\/li>\n
  509. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  510. \n
     <\/div>\n<\/li>\n
  511. \n
    # print (np.trunc(Z))<\/span><\/div>\n<\/li>\n
  512. \n
     <\/div>\n<\/li>\n
  513. \n
    37<\/span>. \u521b\u5efa\u4e00\u4e2a5×5\u7684\u77e9\u9635\uff0c\u5176\u4e2d\u6bcf\u884c\u7684\u6570\u503c\u8303\u56f4\u4ece0<\/span>\u52304<\/span><\/div>\n<\/li>\n
  514. \n
     <\/div>\n<\/li>\n
  515. \n
    (<\/span>\u63d0\u793a: np.arange<\/span>)<\/span><\/div>\n<\/li>\n
  516. \n
     <\/div>\n<\/li>\n
  517. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  518. \n
     <\/div>\n<\/li>\n
  519. \n
    # Z = np.zeros((5,5))<\/span><\/div>\n<\/li>\n
  520. \n
     <\/div>\n<\/li>\n
  521. \n
    # Z += np.arange(5)<\/span><\/div>\n<\/li>\n
  522. \n
     <\/div>\n<\/li>\n
  523. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  524. \n
     <\/div>\n<\/li>\n
  525. \n
    38<\/span>. \u901a\u8fc7\u8003\u8651\u4e00\u4e2a\u53ef\u751f\u621010<\/span>\u4e2a\u6574\u6570\u7684\u51fd\u6570\uff0c\u6765\u6784\u5efa\u4e00\u4e2a\u6570\u7ec4<\/div>\n<\/li>\n
  526. \n
     <\/div>\n<\/li>\n
  527. \n
    (<\/span>\u63d0\u793a: np.fromiter<\/span>)<\/span><\/div>\n<\/li>\n
  528. \n
     <\/div>\n<\/li>\n
  529. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  530. \n
     <\/div>\n<\/li>\n
  531. \n
    # def generate():<\/span><\/div>\n<\/li>\n
  532. \n
     <\/div>\n<\/li>\n
  533. \n
    # for x in range(10):<\/span><\/div>\n<\/li>\n
  534. \n
     <\/div>\n<\/li>\n
  535. \n
    # yield x<\/span><\/div>\n<\/li>\n
  536. \n
     <\/div>\n<\/li>\n
  537. \n
    # Z = np.fromiter(generate(),dtype=float,count=-1)<\/span><\/div>\n<\/li>\n
  538. \n
     <\/div>\n<\/li>\n
  539. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  540. \n
     <\/div>\n<\/li>\n
  541. \n
    39<\/span>. \u521b\u5efa\u4e00\u4e2a\u957f\u5ea6\u4e3a10<\/span>\u7684\u968f\u673a\u5411\u91cf\uff0c\u5176\u503c\u57df\u8303\u56f4\u4ece0<\/span>\u52301<\/span>\uff0c\u4f46\u662f\u4e0d\u5305\u62ec0<\/span>\u548c1<\/span><\/div>\n<\/li>\n
  542. \n
     <\/div>\n<\/li>\n
  543. \n
    (<\/span>\u63d0\u793a: np.linspace<\/span>)<\/span><\/div>\n<\/li>\n
  544. \n
     <\/div>\n<\/li>\n
  545. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  546. \n
     <\/div>\n<\/li>\n
  547. \n
    # Z = np.linspace(0,1,11,endpoint=False)[1:]<\/span><\/div>\n<\/li>\n
  548. \n
     <\/div>\n<\/li>\n
  549. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  550. \n
     <\/div>\n<\/li>\n
  551. \n
    40<\/span>. \u521b\u5efa\u4e00\u4e2a\u957f\u5ea6\u4e3a10<\/span>\u7684\u968f\u673a\u5411\u91cf\uff0c\u5e76\u5c06\u5176\u6392\u5e8f<\/div>\n<\/li>\n
  552. \n
     <\/div>\n<\/li>\n
  553. \n
    (<\/span>\u63d0\u793a: sort)<\/span><\/div>\n<\/li>\n
  554. \n
     <\/div>\n<\/li>\n
  555. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  556. \n
     <\/div>\n<\/li>\n
  557. \n
    # Z = np.random.random(10)<\/span><\/div>\n<\/li>\n
  558. \n
     <\/div>\n<\/li>\n
  559. \n
    # Z.sort()<\/span><\/div>\n<\/li>\n
  560. \n
     <\/div>\n<\/li>\n
  561. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  562. \n
     <\/div>\n<\/li>\n
  563. \n
    41<\/span>.\u5bf9\u4e8e\u4e00\u4e2a\u5c0f\u6570\u7ec4\uff0c\u5982\u4f55\u7528\u6bd4 np.sum<\/span>\u66f4\u5feb\u7684\u65b9\u5f0f\u5bf9\u5176\u6c42\u548c\uff1f<\/div>\n<\/li>\n
  564. \n
     <\/div>\n<\/li>\n
  565. \n
    (<\/span>\u63d0\u793a: np.add<\/span>.reduce<\/span>)<\/span><\/div>\n<\/li>\n
  566. \n
     <\/div>\n<\/li>\n
  567. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  568. \n
     <\/div>\n<\/li>\n
  569. \n
    # Z = np.arange(10)<\/span><\/div>\n<\/li>\n
  570. \n
     <\/div>\n<\/li>\n
  571. \n
    # np.add.reduce(Z)<\/span><\/div>\n<\/li>\n
  572. \n
     <\/div>\n<\/li>\n
  573. \n
    42<\/span>. \u5bf9\u4e8e\u4e24\u4e2a\u968f\u673a\u6570\u7ec4A\u548cB\uff0c\u68c0\u67e5\u5b83\u4eec\u662f\u5426\u76f8\u7b49<\/div>\n<\/li>\n
  574. \n
     <\/div>\n<\/li>\n
  575. \n
    (<\/span>\u63d0\u793a: np.allclose<\/span>,<\/span> np.array_equal<\/span>)<\/span><\/div>\n<\/li>\n
  576. \n
     <\/div>\n<\/li>\n
  577. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  578. \n
     <\/div>\n<\/li>\n
  579. \n
    # A = np.random.randint(0,2,5)<\/span><\/div>\n<\/li>\n
  580. \n
     <\/div>\n<\/li>\n
  581. \n
    # B = np.random.randint(0,2,5)<\/span><\/div>\n<\/li>\n
  582. \n
     <\/div>\n<\/li>\n
  583. \n
    # # Assuming identical shape of the arrays and a tolerance for the comparison of values<\/span><\/div>\n<\/li>\n
  584. \n
     <\/div>\n<\/li>\n
  585. \n
    # equal = np.allclose(A,B)<\/span><\/div>\n<\/li>\n
  586. \n
     <\/div>\n<\/li>\n
  587. \n
    # print(equal)<\/span><\/div>\n<\/li>\n
  588. \n
     <\/div>\n<\/li>\n
  589. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  590. \n
     <\/div>\n<\/li>\n
  591. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  592. \n
     <\/div>\n<\/li>\n
  593. \n
    # # Checking both the shape and the element values, no tolerance (values have to be exactly equal)<\/span><\/div>\n<\/li>\n
  594. \n
     <\/div>\n<\/li>\n
  595. \n
    # equal = np.array_equal(A,B)<\/span><\/div>\n<\/li>\n
  596. \n
     <\/div>\n<\/li>\n
  597. \n
    # print(equal)<\/span><\/div>\n<\/li>\n
  598. \n
     <\/div>\n<\/li>\n
  599. \n
    43<\/span>. \u521b\u5efa\u4e00\u4e2a\u53ea\u8bfb\u6570\u7ec4(<\/span>read-only)<\/span><\/div>\n<\/li>\n
  600. \n
     <\/div>\n<\/li>\n
  601. \n
    (<\/span>\u63d0\u793a: flags.writeable<\/span>)<\/span><\/div>\n<\/li>\n
  602. \n
     <\/div>\n<\/li>\n
  603. \n
    # \u4f7f\u7528\u5982\u4e0b\u8fc7\u7a0b\u5b9e\u73b0<\/span><\/div>\n<\/li>\n
  604. \n
     <\/div>\n<\/li>\n
  605. \n
    Z=<\/span>np.zeros<\/span>(<\/span>10<\/span>)<\/span><\/div>\n<\/li>\n
  606. \n
     <\/div>\n<\/li>\n
  607. \n
    Z.flags<\/span>.writeable<\/span>=<\/span>False<\/span><\/div>\n<\/li>\n
  608. \n
     <\/div>\n<\/li>\n
  609. \n
    Z[<\/span>0<\/span>]<\/span> =<\/span>1<\/span><\/div>\n<\/li>\n
  610. \n
     <\/div>\n<\/li>\n
  611. \n
    —————————————————————————<\/div>\n<\/li>\n
  612. \n
     <\/div>\n<\/li>\n
  613. \n
    ValueErrorTraceback(<\/span>mostrecentcalllast)<\/span><\/div>\n<\/li>\n
  614. \n
     <\/div>\n<\/li>\n
  615. \n
    <<\/span>ipython-input-54<\/span>-6fd4c6570dd1><\/span>in<<\/span>module><\/span>(<\/span>)<\/span><\/div>\n<\/li>\n
  616. \n
     <\/div>\n<\/li>\n
  617. \n
    1Z=<\/span>np.zeros<\/span>(<\/span>10<\/span>)<\/span><\/div>\n<\/li>\n
  618. \n
     <\/div>\n<\/li>\n
  619. \n
    2Z.flags<\/span>.writeable<\/span>=<\/span>False<\/span><\/div>\n<\/li>\n
  620. \n
     <\/div>\n<\/li>\n
  621. \n
    —-><\/span>3Z[<\/span>0<\/span>]<\/span> =<\/span>1<\/span><\/div>\n<\/li>\n
  622. \n
     <\/div>\n<\/li>\n
  623. \n
    ValueError<\/span>: assignmentdestinationisread-only<\/div>\n<\/li>\n
  624. \n
     <\/div>\n<\/li>\n
  625. \n
    44<\/span>. \u5c06\u7b1b\u5361\u5c14\u5750\u6807\u4e0b\u7684\u4e00\u4e2a10×2\u7684\u77e9\u9635\u8f6c\u6362\u4e3a\u6781\u5750\u6807\u5f62\u5f0f<\/div>\n<\/li>\n
  626. \n
     <\/div>\n<\/li>\n
  627. \n
    (<\/span>hint: np.sqrt<\/span>,<\/span> np.arctan2<\/span>)<\/span><\/div>\n<\/li>\n
  628. \n
     <\/div>\n<\/li>\n
  629. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  630. \n
     <\/div>\n<\/li>\n
  631. \n
    # Z = np.random.random((10,2))<\/span><\/div>\n<\/li>\n
  632. \n
     <\/div>\n<\/li>\n
  633. \n
    # X,Y = Z[:,0], Z[:,1]<\/span><\/div>\n<\/li>\n
  634. \n
     <\/div>\n<\/li>\n
  635. \n
    # R = np.sqrt(X**2+Y**2)<\/span><\/div>\n<\/li>\n
  636. \n
     <\/div>\n<\/li>\n
  637. \n
    # T = np.arctan2(Y,X)<\/span><\/div>\n<\/li>\n
  638. \n
     <\/div>\n<\/li>\n
  639. \n
    # print (R)<\/span><\/div>\n<\/li>\n
  640. \n
     <\/div>\n<\/li>\n
  641. \n
    # print (T)<\/span><\/div>\n<\/li>\n
  642. \n
     <\/div>\n<\/li>\n
  643. \n
    45<\/span>. \u521b\u5efa\u4e00\u4e2a\u957f\u5ea6\u4e3a10<\/span>\u7684\u5411\u91cf\uff0c\u5e76\u5c06\u5411\u91cf\u4e2d\u6700\u5927\u503c\u66ff\u6362\u4e3a1<\/span><\/div>\n<\/li>\n
  644. \n
     <\/div>\n<\/li>\n
  645. \n
    (<\/span>\u63d0\u793a: argmax)<\/span><\/div>\n<\/li>\n
  646. \n
     <\/div>\n<\/li>\n
  647. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  648. \n
     <\/div>\n<\/li>\n
  649. \n
    # Z = np.random.random(10)<\/span><\/div>\n<\/li>\n
  650. \n
     <\/div>\n<\/li>\n
  651. \n
    # Z[Z.argmax()] = 0<\/span><\/div>\n<\/li>\n
  652. \n
     <\/div>\n<\/li>\n
  653. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  654. \n
     <\/div>\n<\/li>\n
  655. \n
    46<\/span>. \u521b\u5efa\u4e00\u4e2a\u7ed3\u6784\u5316\u6570\u7ec4\uff0c\u5e76\u5b9e\u73b0 x \u548c y \u5750\u6807\u8986\u76d6 [<\/span>0<\/span>,<\/span>1<\/span>]<\/span>x[<\/span>0<\/span>,<\/span>1<\/span>]<\/span> \u533a\u57df<\/div>\n<\/li>\n
  656. \n
     <\/div>\n<\/li>\n
  657. \n
    (<\/span>\u63d0\u793a: np.meshgrid<\/span>)<\/span><\/div>\n<\/li>\n
  658. \n
     <\/div>\n<\/li>\n
  659. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  660. \n
     <\/div>\n<\/li>\n
  661. \n
    # Z = np.zeros((5,5), [(‘x’,float),(‘y’,float)])<\/span><\/div>\n<\/li>\n
  662. \n
     <\/div>\n<\/li>\n
  663. \n
    # Z[‘x’], Z[‘y’] = np.meshgrid(np.linspace(0,1,5),<\/span><\/div>\n<\/li>\n
  664. \n
     <\/div>\n<\/li>\n
  665. \n
    # np.linspace(0,1,5))<\/span><\/div>\n<\/li>\n
  666. \n
     <\/div>\n<\/li>\n
  667. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  668. \n
     <\/div>\n<\/li>\n
  669. \n
    47<\/span>. \u7ed9\u5b9a\u4e24\u4e2a\u6570\u7ec4X\u548cY\uff0c\u6784\u9020Cauchy\u77e9\u9635C (<\/span>Cij =<\/span>1<\/span>\/(<\/span>xi – yj)<\/span>)<\/span><\/div>\n<\/li>\n
  670. \n
     <\/div>\n<\/li>\n
  671. \n
    (<\/span>\u63d0\u793a: np.subtract<\/span>.outer<\/span>)<\/span><\/div>\n<\/li>\n
  672. \n
     <\/div>\n<\/li>\n
  673. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  674. \n
     <\/div>\n<\/li>\n
  675. \n
    # X = np.arange(8)<\/span><\/div>\n<\/li>\n
  676. \n
     <\/div>\n<\/li>\n
  677. \n
    # Y = X + 0.5<\/span><\/div>\n<\/li>\n
  678. \n
     <\/div>\n<\/li>\n
  679. \n
    # C = 1.0 \/ np.subtract.outer(X, Y)<\/span><\/div>\n<\/li>\n
  680. \n
     <\/div>\n<\/li>\n
  681. \n
    # print(np.linalg.det(C))<\/span><\/div>\n<\/li>\n
  682. \n
     <\/div>\n<\/li>\n
  683. \n
    48<\/span>. \u6253\u5370\u6bcf\u4e2anumpy\u6807\u91cf\u7c7b\u578b\u7684\u6700\u5c0f\u503c\u548c\u6700\u5927\u503c\uff1f<\/div>\n<\/li>\n
  684. \n
     <\/div>\n<\/li>\n
  685. \n
    (<\/span>\u63d0\u793a: np.iinfo<\/span>,<\/span> np.finfo<\/span>,<\/span> eps)<\/span><\/div>\n<\/li>\n
  686. \n
     <\/div>\n<\/li>\n
  687. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  688. \n
     <\/div>\n<\/li>\n
  689. \n
    # for dtype in [np.int8, np.int32, np.int64]:<\/span><\/div>\n<\/li>\n
  690. \n
     <\/div>\n<\/li>\n
  691. \n
    # print(np.iinfo(dtype).min)<\/span><\/div>\n<\/li>\n
  692. \n
     <\/div>\n<\/li>\n
  693. \n
    # print(np.iinfo(dtype).max)<\/span><\/div>\n<\/li>\n
  694. \n
     <\/div>\n<\/li>\n
  695. \n
    # for dtype in [np.float32, np.float64]:<\/span><\/div>\n<\/li>\n
  696. \n
     <\/div>\n<\/li>\n
  697. \n
    # print(np.finfo(dtype).min)<\/span><\/div>\n<\/li>\n
  698. \n
     <\/div>\n<\/li>\n
  699. \n
    # print(np.finfo(dtype).max)<\/span><\/div>\n<\/li>\n
  700. \n
     <\/div>\n<\/li>\n
  701. \n
    # print(np.finfo(dtype).eps)<\/span><\/div>\n<\/li>\n
  702. \n
     <\/div>\n<\/li>\n
  703. \n
    49<\/span>. \u5982\u4f55\u6253\u5370\u4e00\u4e2a\u6570\u7ec4\u4e2d\u7684\u6240\u6709\u6570\u503c?<\/div>\n<\/li>\n
  704. \n
     <\/div>\n<\/li>\n
  705. \n
    (<\/span>\u63d0\u793a: np.set_printoptions<\/span>)<\/span><\/div>\n<\/li>\n
  706. \n
     <\/div>\n<\/li>\n
  707. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  708. \n
     <\/div>\n<\/li>\n
  709. \n
    # np.set_printoptions(threshold=np.nan)<\/span><\/div>\n<\/li>\n
  710. \n
     <\/div>\n<\/li>\n
  711. \n
    # Z = np.zeros((16,16))<\/span><\/div>\n<\/li>\n
  712. \n
     <\/div>\n<\/li>\n
  713. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  714. \n
     <\/div>\n<\/li>\n
  715. \n
    50<\/span>. \u7ed9\u5b9a\u6807\u91cf\u65f6\uff0c\u5982\u4f55\u627e\u5230\u6570\u7ec4\u4e2d\u6700\u63a5\u8fd1\u6807\u91cf\u7684\u503c\uff1f<\/div>\n<\/li>\n
  716. \n
     <\/div>\n<\/li>\n
  717. \n
    (<\/span>\u63d0\u793a: argmin)<\/span><\/div>\n<\/li>\n
  718. \n
     <\/div>\n<\/li>\n
  719. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  720. \n
     <\/div>\n<\/li>\n
  721. \n
    # Z = np.arange(100)<\/span><\/div>\n<\/li>\n
  722. \n
     <\/div>\n<\/li>\n
  723. \n
    # v = np.random.uniform(0,100)<\/span><\/div>\n<\/li>\n
  724. \n
     <\/div>\n<\/li>\n
  725. \n
    # index = (np.abs(Z-v)).argmin()<\/span><\/div>\n<\/li>\n
  726. \n
     <\/div>\n<\/li>\n
  727. \n
    # print (Z[index])<\/span><\/div>\n<\/li>\n
  728. \n
     <\/div>\n<\/li>\n
  729. \n
    51<\/span>. \u521b\u5efa\u4e00\u4e2a\u8868\u793a\u4f4d\u7f6e(<\/span>x,<\/span>y)<\/span>\u548c\u989c\u8272(<\/span>r,<\/span>g,<\/span>b)<\/span>\u7684\u7ed3\u6784\u5316\u6570\u7ec4<\/div>\n<\/li>\n
  730. \n
     <\/div>\n<\/li>\n
  731. \n
    (<\/span>\u63d0\u793a: dtype)<\/span><\/div>\n<\/li>\n
  732. \n
     <\/div>\n<\/li>\n
  733. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  734. \n
     <\/div>\n<\/li>\n
  735. \n
    # Z = np.zeros(10, [ (‘position’, [ (‘x’, float, 1),<\/span><\/div>\n<\/li>\n
  736. \n
     <\/div>\n<\/li>\n
  737. \n
    # (‘y’, float, 1)]),<\/span><\/div>\n<\/li>\n
  738. \n
     <\/div>\n<\/li>\n
  739. \n
    # (‘color’, [ (‘r’, float, 1),<\/span><\/div>\n<\/li>\n
  740. \n
     <\/div>\n<\/li>\n
  741. \n
    # (‘g’, float, 1),<\/span><\/div>\n<\/li>\n
  742. \n
     <\/div>\n<\/li>\n
  743. \n
    # (‘b’, float, 1)])])<\/span><\/div>\n<\/li>\n
  744. \n
     <\/div>\n<\/li>\n
  745. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  746. \n
     <\/div>\n<\/li>\n
  747. \n
    52<\/span>. \u5bf9\u4e00\u4e2a\u8868\u793a\u5750\u6807\u5f62\u72b6\u4e3a(<\/span>100<\/span>,<\/span>2<\/span>)<\/span>\u7684\u968f\u673a\u5411\u91cf\uff0c\u627e\u5230\u70b9\u4e0e\u70b9\u7684\u8ddd\u79bb<\/div>\n<\/li>\n
  748. \n
     <\/div>\n<\/li>\n
  749. \n
    (<\/span>\u63d0\u793a: np.atleast_2d<\/span>,<\/span> T,<\/span> np.sqrt<\/span>)<\/span><\/div>\n<\/li>\n
  750. \n
     <\/div>\n<\/li>\n
  751. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  752. \n
     <\/div>\n<\/li>\n
  753. \n
    # Z = np.random.random((10,2))<\/span><\/div>\n<\/li>\n
  754. \n
     <\/div>\n<\/li>\n
  755. \n
    # X,Y = np.atleast_2d(Z[:,0], Z[:,1])<\/span><\/div>\n<\/li>\n
  756. \n
     <\/div>\n<\/li>\n
  757. \n
    # D = np.sqrt( (X-X.T)**2 + (Y-Y.T)**2)<\/span><\/div>\n<\/li>\n
  758. \n
     <\/div>\n<\/li>\n
  759. \n
    # print (D)<\/span><\/div>\n<\/li>\n
  760. \n
     <\/div>\n<\/li>\n
  761. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  762. \n
     <\/div>\n<\/li>\n
  763. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  764. \n
     <\/div>\n<\/li>\n
  765. \n
    # # Much faster with scipy<\/span><\/div>\n<\/li>\n
  766. \n
     <\/div>\n<\/li>\n
  767. \n
    # import scipy<\/span><\/div>\n<\/li>\n
  768. \n
     <\/div>\n<\/li>\n
  769. \n
    # # Thanks Gavin Heverly-Coulson (#issue 1)<\/span><\/div>\n<\/li>\n
  770. \n
     <\/div>\n<\/li>\n
  771. \n
    # import scipy.spatial<\/span><\/div>\n<\/li>\n
  772. \n
     <\/div>\n<\/li>\n
  773. \n
    # D = scipy.spatial.distance.cdist(Z,Z)<\/span><\/div>\n<\/li>\n
  774. \n
     <\/div>\n<\/li>\n
  775. \n
    # print (D)<\/span><\/div>\n<\/li>\n
  776. \n
     <\/div>\n<\/li>\n
  777. \n
    53<\/span>. \u5982\u4f55\u5c0632<\/span>\u4f4d\u7684\u6d6e\u70b9\u6570(<\/span>float<\/span>)<\/span>\u8f6c\u6362\u4e3a\u5bf9\u5e94\u7684\u6574\u6570(<\/span>integer)<\/span>?<\/div>\n<\/li>\n
  778. \n
     <\/div>\n<\/li>\n
  779. \n
    (<\/span>\u63d0\u793a: astype(<\/span>copy<\/span>=<\/span>False<\/span>)<\/span>)<\/span><\/div>\n<\/li>\n
  780. \n
     <\/div>\n<\/li>\n
  781. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  782. \n
     <\/div>\n<\/li>\n
  783. \n
    # Z = np.arange(10, dtype=np.int32)<\/span><\/div>\n<\/li>\n
  784. \n
     <\/div>\n<\/li>\n
  785. \n
    # Z = Z.astype(np.float32, copy=False)<\/span><\/div>\n<\/li>\n
  786. \n
     <\/div>\n<\/li>\n
  787. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  788. \n
     <\/div>\n<\/li>\n
  789. \n
    54<\/span>. \u5982\u4f55\u8bfb\u53d6\u4ee5\u4e0b\u6587\u4ef6?<\/div>\n<\/li>\n
  790. \n
     <\/div>\n<\/li>\n
  791. \n
    (<\/span>\u63d0\u793a: np.genfromtxt<\/span>)<\/span><\/div>\n<\/li>\n
  792. \n
     <\/div>\n<\/li>\n
  793. \n
    1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span><\/div>\n<\/li>\n
  794. \n
     <\/div>\n<\/li>\n
  795. \n
    6<\/span>,<\/span> ,<\/span> ,<\/span> 7<\/span>,<\/span> 8<\/span><\/div>\n<\/li>\n
  796. \n
     <\/div>\n<\/li>\n
  797. \n
    ,<\/span> ,<\/span> 9<\/span>,<\/span>10<\/span>,<\/span>11<\/span><\/div>\n<\/li>\n
  798. \n
     <\/div>\n<\/li>\n
  799. \n
    \u53c2\u8003\u94fe\u63a5<\/div>\n<\/li>\n
  800. \n
     <\/div>\n<\/li>\n
  801. \n
    55<\/span>. \u5bf9\u4e8enumpy\u6570\u7ec4\uff0cenumerate<\/span>\u7684\u7b49\u4ef7\u64cd\u4f5c\u662f\u4ec0\u4e48\uff1f<\/div>\n<\/li>\n
  802. \n
     <\/div>\n<\/li>\n
  803. \n
    (<\/span>\u63d0\u793a: np.ndenumerate<\/span>,<\/span> np.ndindex<\/span>)<\/span><\/div>\n<\/li>\n
  804. \n
     <\/div>\n<\/li>\n
  805. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  806. \n
     <\/div>\n<\/li>\n
  807. \n
    # Z = np.arange(9).reshape(3,3)<\/span><\/div>\n<\/li>\n
  808. \n
     <\/div>\n<\/li>\n
  809. \n
    # for index, value in np.ndenumerate(Z):<\/span><\/div>\n<\/li>\n
  810. \n
     <\/div>\n<\/li>\n
  811. \n
    # print (index, value)<\/span><\/div>\n<\/li>\n
  812. \n
     <\/div>\n<\/li>\n
  813. \n
    # for index in np.ndindex(Z.shape):<\/span><\/div>\n<\/li>\n
  814. \n
     <\/div>\n<\/li>\n
  815. \n
    # print (index, Z[index])<\/span><\/div>\n<\/li>\n
  816. \n
     <\/div>\n<\/li>\n
  817. \n
    56<\/span>. \u751f\u6210\u4e00\u4e2a\u901a\u7528\u7684\u4e8c\u7ef4Gaussian-like\u6570\u7ec4<\/div>\n<\/li>\n
  818. \n
     <\/div>\n<\/li>\n
  819. \n
    (<\/span>\u63d0\u793a: np.meshgrid<\/span>,<\/span> np.exp<\/span>)<\/span><\/div>\n<\/li>\n
  820. \n
     <\/div>\n<\/li>\n
  821. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  822. \n
     <\/div>\n<\/li>\n
  823. \n
    # X, Y = np.meshgrid(np.linspace(-1,1,10), np.linspace(-1,1,10))<\/span><\/div>\n<\/li>\n
  824. \n
     <\/div>\n<\/li>\n
  825. \n
    # D = np.sqrt(X*X+Y*Y)<\/span><\/div>\n<\/li>\n
  826. \n
     <\/div>\n<\/li>\n
  827. \n
    # sigma, mu = 1.0, 0.0<\/span><\/div>\n<\/li>\n
  828. \n
     <\/div>\n<\/li>\n
  829. \n
    # G = np.exp(-( (D-mu)**2 \/ ( 2.0 * sigma**2 ) ) )<\/span><\/div>\n<\/li>\n
  830. \n
     <\/div>\n<\/li>\n
  831. \n
    # print (G)<\/span><\/div>\n<\/li>\n
  832. \n
     <\/div>\n<\/li>\n
  833. \n
    57<\/span>. \u5bf9\u4e00\u4e2a\u4e8c\u7ef4\u6570\u7ec4\uff0c\u5982\u4f55\u5728\u5176\u5185\u90e8\u968f\u673a\u653e\u7f6ep\u4e2a\u5143\u7d20?<\/div>\n<\/li>\n
  834. \n
     <\/div>\n<\/li>\n
  835. \n
    (<\/span>\u63d0\u793a: np.put<\/span>,<\/span> np.random<\/span>.choice<\/span>)<\/span><\/div>\n<\/li>\n
  836. \n
     <\/div>\n<\/li>\n
  837. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  838. \n
     <\/div>\n<\/li>\n
  839. \n
    # n = 10<\/span><\/div>\n<\/li>\n
  840. \n
     <\/div>\n<\/li>\n
  841. \n
    # p = 3<\/span><\/div>\n<\/li>\n
  842. \n
     <\/div>\n<\/li>\n
  843. \n
    # Z = np.zeros((n,n))<\/span><\/div>\n<\/li>\n
  844. \n
     <\/div>\n<\/li>\n
  845. \n
    # np.put(Z, np.random.choice(range(n*n), p, replace=False),1)<\/span><\/div>\n<\/li>\n
  846. \n
     <\/div>\n<\/li>\n
  847. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  848. \n
     <\/div>\n<\/li>\n
  849. \n
    58<\/span>. \u51cf\u53bb\u4e00\u4e2a\u77e9\u9635\u4e2d\u7684\u6bcf\u4e00\u884c\u7684\u5e73\u5747\u503c<\/div>\n<\/li>\n
  850. \n
     <\/div>\n<\/li>\n
  851. \n
    (<\/span>\u63d0\u793a: mean(<\/span>axis=,<\/span>keepdims=<\/span>)<\/span>)<\/span><\/div>\n<\/li>\n
  852. \n
     <\/div>\n<\/li>\n
  853. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  854. \n
     <\/div>\n<\/li>\n
  855. \n
    # X = np.random.rand(5, 10)<\/span><\/div>\n<\/li>\n
  856. \n
     <\/div>\n<\/li>\n
  857. \n
    # # Recent versions of numpy<\/span><\/div>\n<\/li>\n
  858. \n
     <\/div>\n<\/li>\n
  859. \n
    # Y = X – X.mean(axis=1, keepdims=True)<\/span><\/div>\n<\/li>\n
  860. \n
     <\/div>\n<\/li>\n
  861. \n
    # print(Y)<\/span><\/div>\n<\/li>\n
  862. \n
     <\/div>\n<\/li>\n
  863. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  864. \n
     <\/div>\n<\/li>\n
  865. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  866. \n
     <\/div>\n<\/li>\n
  867. \n
    # # Older versions of numpy<\/span><\/div>\n<\/li>\n
  868. \n
     <\/div>\n<\/li>\n
  869. \n
    # Y = X – X.mean(axis=1).reshape(-1, 1)<\/span><\/div>\n<\/li>\n
  870. \n
     <\/div>\n<\/li>\n
  871. \n
    # print (Y)<\/span><\/div>\n<\/li>\n
  872. \n
     <\/div>\n<\/li>\n
  873. \n
    59<\/span>. \u5982\u4f55\u901a\u8fc7\u7b2cn\u5217\u5bf9\u4e00\u4e2a\u6570\u7ec4\u8fdb\u884c\u6392\u5e8f?<\/div>\n<\/li>\n
  874. \n
     <\/div>\n<\/li>\n
  875. \n
    (<\/span>\u63d0\u793a: argsort)<\/span><\/div>\n<\/li>\n
  876. \n
     <\/div>\n<\/li>\n
  877. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  878. \n
     <\/div>\n<\/li>\n
  879. \n
    # Z = np.random.randint(0,10,(3,3))<\/span><\/div>\n<\/li>\n
  880. \n
     <\/div>\n<\/li>\n
  881. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  882. \n
     <\/div>\n<\/li>\n
  883. \n
    # print (Z[Z[:,1].argsort()])<\/span><\/div>\n<\/li>\n
  884. \n
     <\/div>\n<\/li>\n
  885. \n
    60<\/span>. \u5982\u4f55\u68c0\u67e5\u4e00\u4e2a\u4e8c\u7ef4\u6570\u7ec4\u662f\u5426\u6709\u7a7a\u5217\uff1f<\/div>\n<\/li>\n
  886. \n
     <\/div>\n<\/li>\n
  887. \n
    (<\/span>\u63d0\u793a: any<\/span>,<\/span> ~<\/span>)<\/span><\/div>\n<\/li>\n
  888. \n
     <\/div>\n<\/li>\n
  889. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  890. \n
     <\/div>\n<\/li>\n
  891. \n
    # Z = np.random.randint(0,3,(3,10))<\/span><\/div>\n<\/li>\n
  892. \n
     <\/div>\n<\/li>\n
  893. \n
    # print ((~Z.any(axis=0)).any())<\/span><\/div>\n<\/li>\n
  894. \n
     <\/div>\n<\/li>\n
  895. \n
    61<\/span>. \u4ece\u6570\u7ec4\u4e2d\u7684\u7ed9\u5b9a\u503c\u4e2d\u627e\u51fa\u6700\u8fd1\u7684\u503c<\/div>\n<\/li>\n
  896. \n
     <\/div>\n<\/li>\n
  897. \n
    (<\/span>\u63d0\u793a: np.abs<\/span>,<\/span> argmin,<\/span> flat)<\/span><\/div>\n<\/li>\n
  898. \n
     <\/div>\n<\/li>\n
  899. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  900. \n
     <\/div>\n<\/li>\n
  901. \n
    # Z = np.random.uniform(0,1,10)<\/span><\/div>\n<\/li>\n
  902. \n
     <\/div>\n<\/li>\n
  903. \n
    # z = 0.5<\/span><\/div>\n<\/li>\n
  904. \n
     <\/div>\n<\/li>\n
  905. \n
    # m = Z.flat[np.abs(Z – z).argmin()]<\/span><\/div>\n<\/li>\n
  906. \n
     <\/div>\n<\/li>\n
  907. \n
    # print (m)<\/span><\/div>\n<\/li>\n
  908. \n
     <\/div>\n<\/li>\n
  909. \n
    62<\/span>. \u5982\u4f55\u7528\u8fed\u4ee3\u5668(<\/span>iterator)<\/span>\u8ba1\u7b97\u4e24\u4e2a\u5206\u522b\u5177\u6709\u5f62\u72b6(<\/span>1<\/span>,<\/span>3<\/span>)<\/span>\u548c(<\/span>3<\/span>,<\/span>1<\/span>)<\/span>\u7684\u6570\u7ec4?<\/div>\n<\/li>\n
  910. \n
     <\/div>\n<\/li>\n
  911. \n
    (<\/span>\u63d0\u793a: np.nditer<\/span>)<\/span><\/div>\n<\/li>\n
  912. \n
     <\/div>\n<\/li>\n
  913. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  914. \n
     <\/div>\n<\/li>\n
  915. \n
    # A = np.arange(3).reshape(3,1)<\/span><\/div>\n<\/li>\n
  916. \n
     <\/div>\n<\/li>\n
  917. \n
    # B = np.arange(3).reshape(1,3)<\/span><\/div>\n<\/li>\n
  918. \n
     <\/div>\n<\/li>\n
  919. \n
    # it = np.nditer([A,B,None])<\/span><\/div>\n<\/li>\n
  920. \n
     <\/div>\n<\/li>\n
  921. \n
    # for x,y,z in it:<\/span><\/div>\n<\/li>\n
  922. \n
     <\/div>\n<\/li>\n
  923. \n
    # z[…] = x + y<\/span><\/div>\n<\/li>\n
  924. \n
     <\/div>\n<\/li>\n
  925. \n
    # print (it.operands[2])<\/span><\/div>\n<\/li>\n
  926. \n
     <\/div>\n<\/li>\n
  927. \n
    63<\/span>. \u521b\u5efa\u4e00\u4e2a\u5177\u6709name\u5c5e\u6027\u7684\u6570\u7ec4\u7c7b<\/div>\n<\/li>\n
  928. \n
     <\/div>\n<\/li>\n
  929. \n
    (<\/span>\u63d0\u793a: class<\/span>\u65b9\u6cd5)<\/span><\/div>\n<\/li>\n
  930. \n
     <\/div>\n<\/li>\n
  931. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  932. \n
     <\/div>\n<\/li>\n
  933. \n
    # class NamedArray(np.ndarray):<\/span><\/div>\n<\/li>\n
  934. \n
     <\/div>\n<\/li>\n
  935. \n
    # def __new__(cls, array, name="no name"):<\/span><\/div>\n<\/li>\n
  936. \n
     <\/div>\n<\/li>\n
  937. \n
    # obj = np.asarray(array).view(cls)<\/span><\/div>\n<\/li>\n
  938. \n
     <\/div>\n<\/li>\n
  939. \n
    # obj.name = name<\/span><\/div>\n<\/li>\n
  940. \n
     <\/div>\n<\/li>\n
  941. \n
    # return obj<\/span><\/div>\n<\/li>\n
  942. \n
     <\/div>\n<\/li>\n
  943. \n
    # def __array_finalize__(self, obj):<\/span><\/div>\n<\/li>\n
  944. \n
     <\/div>\n<\/li>\n
  945. \n
    # if obj is None: return<\/span><\/div>\n<\/li>\n
  946. \n
     <\/div>\n<\/li>\n
  947. \n
    # http:\/\/self.info = getattr(obj, ‘name’, "no name")<\/span><\/div>\n<\/li>\n
  948. \n
     <\/div>\n<\/li>\n
  949. \n
    # Z = NamedArray(np.arange(10), "range_10")<\/span><\/div>\n<\/li>\n
  950. \n
     <\/div>\n<\/li>\n
  951. \n
    # print (Z.name)<\/span><\/div>\n<\/li>\n
  952. \n
     <\/div>\n<\/li>\n
  953. \n
    64<\/span>. \u8003\u8651\u4e00\u4e2a\u7ed9\u5b9a\u7684\u5411\u91cf\uff0c\u5982\u4f55\u5bf9\u7531\u7b2c\u4e8c\u4e2a\u5411\u91cf\u7d22\u5f15\u7684\u6bcf\u4e2a\u5143\u7d20\u52a01<\/span>(<\/span>\u5c0f\u5fc3\u91cd\u590d\u7684\u7d22\u5f15)<\/span>?<\/div>\n<\/li>\n
  954. \n
     <\/div>\n<\/li>\n
  955. \n
    (<\/span>\u63d0\u793a: np.bincount<\/span> | np.add<\/span>.at<\/span>)<\/span><\/div>\n<\/li>\n
  956. \n
     <\/div>\n<\/li>\n
  957. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  958. \n
     <\/div>\n<\/li>\n
  959. \n
    # Z = np.ones(10)<\/span><\/div>\n<\/li>\n
  960. \n
     <\/div>\n<\/li>\n
  961. \n
    # I = np.random.randint(0,len(Z),20)<\/span><\/div>\n<\/li>\n
  962. \n
     <\/div>\n<\/li>\n
  963. \n
    # Z += np.bincount(I, minlength=len(Z))<\/span><\/div>\n<\/li>\n
  964. \n
     <\/div>\n<\/li>\n
  965. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  966. \n
     <\/div>\n<\/li>\n
  967. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  968. \n
     <\/div>\n<\/li>\n
  969. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  970. \n
     <\/div>\n<\/li>\n
  971. \n
    # np.add.at(Z, I, 1)<\/span><\/div>\n<\/li>\n
  972. \n
     <\/div>\n<\/li>\n
  973. \n
    # print(Z)<\/span><\/div>\n<\/li>\n
  974. \n
     <\/div>\n<\/li>\n
  975. \n
    65<\/span>. \u6839\u636e\u7d22\u5f15\u5217\u8868(<\/span>I)<\/span>\uff0c\u5982\u4f55\u5c06\u5411\u91cf(<\/span>X)<\/span>\u7684\u5143\u7d20\u7d2f\u52a0\u5230\u6570\u7ec4(<\/span>F)<\/span>?<\/div>\n<\/li>\n
  976. \n
     <\/div>\n<\/li>\n
  977. \n
    (<\/span>\u63d0\u793a: np.bincount<\/span>)<\/span><\/div>\n<\/li>\n
  978. \n
     <\/div>\n<\/li>\n
  979. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  980. \n
     <\/div>\n<\/li>\n
  981. \n
    # X = [1,2,3,4,5,6]<\/span><\/div>\n<\/li>\n
  982. \n
     <\/div>\n<\/li>\n
  983. \n
    # I = [1,3,9,3,4,1]<\/span><\/div>\n<\/li>\n
  984. \n
     <\/div>\n<\/li>\n
  985. \n
    # F = np.bincount(I,X)<\/span><\/div>\n<\/li>\n
  986. \n
     <\/div>\n<\/li>\n
  987. \n
    # print (F)<\/span><\/div>\n<\/li>\n
  988. \n
     <\/div>\n<\/li>\n
  989. \n
    66<\/span>. \u8003\u8651\u4e00\u4e2a(<\/span>dtype=<\/span>ubyte)<\/span> \u7684 (<\/span>w,<\/span>h,<\/span>3<\/span>)<\/span>\u56fe\u50cf\uff0c\u8ba1\u7b97\u5176\u552f\u4e00\u989c\u8272\u7684\u6570\u91cf<\/div>\n<\/li>\n
  990. \n
     <\/div>\n<\/li>\n
  991. \n
    (<\/span>\u63d0\u793a: np.unique<\/span>)<\/span><\/div>\n<\/li>\n
  992. \n
     <\/div>\n<\/li>\n
  993. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  994. \n
     <\/div>\n<\/li>\n
  995. \n
    # w,h = 16,16<\/span><\/div>\n<\/li>\n
  996. \n
     <\/div>\n<\/li>\n
  997. \n
    # I = np.random.randint(0,2,(h,w,3)).astype(np.ubyte)<\/span><\/div>\n<\/li>\n
  998. \n
     <\/div>\n<\/li>\n
  999. \n
    # #Note that we should compute 256*256 first.<\/span><\/div>\n<\/li>\n
  1000. \n
     <\/div>\n<\/li>\n
  1001. \n
    # #Otherwise numpy will only promote F.dtype to ‘uint16’ and overfolw will occur<\/span><\/div>\n<\/li>\n
  1002. \n
     <\/div>\n<\/li>\n
  1003. \n
    # F = I[…,0]*(256*256) + I[…,1]*256 +I[…,2]<\/span><\/div>\n<\/li>\n
  1004. \n
     <\/div>\n<\/li>\n
  1005. \n
    # n = len(np.unique(F))<\/span><\/div>\n<\/li>\n
  1006. \n
     <\/div>\n<\/li>\n
  1007. \n
    # print (n)<\/span><\/div>\n<\/li>\n
  1008. \n
     <\/div>\n<\/li>\n
  1009. \n
    67<\/span>. \u8003\u8651\u4e00\u4e2a\u56db\u7ef4\u6570\u7ec4\uff0c\u5982\u4f55\u4e00\u6b21\u6027\u8ba1\u7b97\u51fa\u6700\u540e\u4e24\u4e2a\u8f74(<\/span>axis)<\/span>\u7684\u548c\uff1f<\/div>\n<\/li>\n
  1010. \n
     <\/div>\n<\/li>\n
  1011. \n
    (<\/span>\u63d0\u793a: sum<\/span>(<\/span>axis=<\/span>(<\/span>–2<\/span>,<\/span>–1<\/span>)<\/span>)<\/span>)<\/span><\/div>\n<\/li>\n
  1012. \n
     <\/div>\n<\/li>\n
  1013. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1014. \n
     <\/div>\n<\/li>\n
  1015. \n
    # A = np.random.randint(0,10,(3,4,3,4))<\/span><\/div>\n<\/li>\n
  1016. \n
     <\/div>\n<\/li>\n
  1017. \n
    # # solution by passing a tuple of axes (introduced in numpy 1.7.0)<\/span><\/div>\n<\/li>\n
  1018. \n
     <\/div>\n<\/li>\n
  1019. \n
    # sum = A.sum(axis=(-2,-1))<\/span><\/div>\n<\/li>\n
  1020. \n
     <\/div>\n<\/li>\n
  1021. \n
    # print (sum)<\/span><\/div>\n<\/li>\n
  1022. \n
     <\/div>\n<\/li>\n
  1023. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1024. \n
     <\/div>\n<\/li>\n
  1025. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  1026. \n
     <\/div>\n<\/li>\n
  1027. \n
    # sum = A.reshape(A.shape[:-2] + (-1,)).sum(axis=-1)<\/span><\/div>\n<\/li>\n
  1028. \n
     <\/div>\n<\/li>\n
  1029. \n
    # print (sum)<\/span><\/div>\n<\/li>\n
  1030. \n
     <\/div>\n<\/li>\n
  1031. \n
    68<\/span>. \u8003\u8651\u4e00\u4e2a\u4e00\u7ef4\u5411\u91cfD\uff0c\u5982\u4f55\u4f7f\u7528\u76f8\u540c\u5927\u5c0f\u7684\u5411\u91cfS\u6765\u8ba1\u7b97D\u5b50\u96c6\u7684\u5747\u503c\uff1f<\/div>\n<\/li>\n
  1032. \n
     <\/div>\n<\/li>\n
  1033. \n
    (<\/span>\u63d0\u793a: np.bincount<\/span>)<\/span><\/div>\n<\/li>\n
  1034. \n
     <\/div>\n<\/li>\n
  1035. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1036. \n
     <\/div>\n<\/li>\n
  1037. \n
    # D = np.random.uniform(0,1,100)<\/span><\/div>\n<\/li>\n
  1038. \n
     <\/div>\n<\/li>\n
  1039. \n
    # S = np.random.randint(0,10,100)<\/span><\/div>\n<\/li>\n
  1040. \n
     <\/div>\n<\/li>\n
  1041. \n
    # D_sums = np.bincount(S, weights=D)<\/span><\/div>\n<\/li>\n
  1042. \n
     <\/div>\n<\/li>\n
  1043. \n
    # D_counts = np.bincount(S)<\/span><\/div>\n<\/li>\n
  1044. \n
     <\/div>\n<\/li>\n
  1045. \n
    # D_means = D_sums \/ D_counts<\/span><\/div>\n<\/li>\n
  1046. \n
     <\/div>\n<\/li>\n
  1047. \n
    # print (D_means)<\/span><\/div>\n<\/li>\n
  1048. \n
     <\/div>\n<\/li>\n
  1049. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1050. \n
     <\/div>\n<\/li>\n
  1051. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  1052. \n
     <\/div>\n<\/li>\n
  1053. \n
    # import pandas as pd<\/span><\/div>\n<\/li>\n
  1054. \n
     <\/div>\n<\/li>\n
  1055. \n
    # print(pd.Series(D).groupby(S).mean())<\/span><\/div>\n<\/li>\n
  1056. \n
     <\/div>\n<\/li>\n
  1057. \n
    69<\/span>. \u5982\u4f55\u83b7\u5f97\u70b9\u79ef dot prodcut\u7684\u5bf9\u89d2\u7ebf?<\/div>\n<\/li>\n
  1058. \n
     <\/div>\n<\/li>\n
  1059. \n
    (<\/span>\u63d0\u793a: np.diag<\/span>)<\/span><\/div>\n<\/li>\n
  1060. \n
     <\/div>\n<\/li>\n
  1061. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1062. \n
     <\/div>\n<\/li>\n
  1063. \n
    # A = np.random.uniform(0,1,(5,5))<\/span><\/div>\n<\/li>\n
  1064. \n
     <\/div>\n<\/li>\n
  1065. \n
    # B = np.random.uniform(0,1,(5,5))<\/span><\/div>\n<\/li>\n
  1066. \n
     <\/div>\n<\/li>\n
  1067. \n
    # # slow version<\/span><\/div>\n<\/li>\n
  1068. \n
     <\/div>\n<\/li>\n
  1069. \n
    # np.diag(np.dot(A, B))<\/span><\/div>\n<\/li>\n
  1070. \n
     <\/div>\n<\/li>\n
  1071. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1072. \n
     <\/div>\n<\/li>\n
  1073. \n
    ## \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  1074. \n
     <\/div>\n<\/li>\n
  1075. \n
    # # Fast version<\/span><\/div>\n<\/li>\n
  1076. \n
     <\/div>\n<\/li>\n
  1077. \n
    # np.sum(A * B.T, axis=1)<\/span><\/div>\n<\/li>\n
  1078. \n
     <\/div>\n<\/li>\n
  1079. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1080. \n
     <\/div>\n<\/li>\n
  1081. \n
    ## \u65b9\u6cd53<\/span><\/div>\n<\/li>\n
  1082. \n
     <\/div>\n<\/li>\n
  1083. \n
    # # Faster version<\/span><\/div>\n<\/li>\n
  1084. \n
     <\/div>\n<\/li>\n
  1085. \n
    # np.einsum("ij,ji->i", A, B)<\/span><\/div>\n<\/li>\n
  1086. \n
     <\/div>\n<\/li>\n
  1087. \n
    70<\/span>. \u8003\u8651\u4e00\u4e2a\u5411\u91cf[<\/span>1<\/span>,<\/span>2<\/span>,<\/span>3<\/span>,<\/span>4<\/span>,<\/span>5<\/span>]<\/span>,<\/span>\u5982\u4f55\u5efa\u7acb\u4e00\u4e2a\u65b0\u7684\u5411\u91cf\uff0c\u5728\u8fd9\u4e2a\u65b0\u5411\u91cf\u4e2d\u6bcf\u4e2a\u503c\u4e4b\u95f4\u67093<\/span>\u4e2a\u8fde\u7eed\u7684\u96f6\uff1f<\/div>\n<\/li>\n
  1088. \n
     <\/div>\n<\/li>\n
  1089. \n
    (<\/span>\u63d0\u793a: array<\/span>[<\/span>::4<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  1090. \n
     <\/div>\n<\/li>\n
  1091. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1092. \n
     <\/div>\n<\/li>\n
  1093. \n
    # Z = np.array([1,2,3,4,5])<\/span><\/div>\n<\/li>\n
  1094. \n
     <\/div>\n<\/li>\n
  1095. \n
    # nz = 3<\/span><\/div>\n<\/li>\n
  1096. \n
     <\/div>\n<\/li>\n
  1097. \n
    # Z0 = np.zeros(len(Z) + (len(Z)-1)*(nz))<\/span><\/div>\n<\/li>\n
  1098. \n
     <\/div>\n<\/li>\n
  1099. \n
    # Z0[::nz+1] = Z<\/span><\/div>\n<\/li>\n
  1100. \n
     <\/div>\n<\/li>\n
  1101. \n
    # print (Z0)<\/span><\/div>\n<\/li>\n
  1102. \n
     <\/div>\n<\/li>\n
  1103. \n
    71<\/span>. \u8003\u8651\u4e00\u4e2a\u7ef4\u5ea6(<\/span>5<\/span>,<\/span>5<\/span>,<\/span>3<\/span>)<\/span>\u7684\u6570\u7ec4\uff0c\u5982\u4f55\u5c06\u5176\u4e0e\u4e00\u4e2a(<\/span>5<\/span>,<\/span>5<\/span>)<\/span>\u7684\u6570\u7ec4\u76f8\u4e58\uff1f<\/div>\n<\/li>\n
  1104. \n
     <\/div>\n<\/li>\n
  1105. \n
    (<\/span>\u63d0\u793a: array<\/span>[<\/span>:,<\/span> :,<\/span> None<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  1106. \n
     <\/div>\n<\/li>\n
  1107. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1108. \n
     <\/div>\n<\/li>\n
  1109. \n
    # A = np.ones((5,5,3))<\/span><\/div>\n<\/li>\n
  1110. \n
     <\/div>\n<\/li>\n
  1111. \n
    # B = 2*np.ones((5,5))<\/span><\/div>\n<\/li>\n
  1112. \n
     <\/div>\n<\/li>\n
  1113. \n
    # print (A * B[:,:,None])<\/span><\/div>\n<\/li>\n
  1114. \n
     <\/div>\n<\/li>\n
  1115. \n
    72<\/span>. \u5982\u4f55\u5bf9\u4e00\u4e2a\u6570\u7ec4\u4e2d\u4efb\u610f\u4e24\u884c\u505a\u4ea4\u6362?<\/div>\n<\/li>\n
  1116. \n
     <\/div>\n<\/li>\n
  1117. \n
    (<\/span>\u63d0\u793a: array<\/span>[<\/span>[<\/span>]<\/span>]<\/span> =<\/span> array<\/span>[<\/span>[<\/span>]<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  1118. \n
     <\/div>\n<\/li>\n
  1119. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1120. \n
     <\/div>\n<\/li>\n
  1121. \n
    # A = np.arange(25).reshape(5,5)<\/span><\/div>\n<\/li>\n
  1122. \n
     <\/div>\n<\/li>\n
  1123. \n
    # A[[0,1]] = A[[1,0]]<\/span><\/div>\n<\/li>\n
  1124. \n
     <\/div>\n<\/li>\n
  1125. \n
    # print (A)<\/span><\/div>\n<\/li>\n
  1126. \n
     <\/div>\n<\/li>\n
  1127. \n
    73<\/span>. \u8003\u8651\u4e00\u4e2a\u53ef\u4ee5\u63cf\u8ff010<\/span>\u4e2a\u4e09\u89d2\u5f62\u7684triplets\uff0c\u627e\u5230\u53ef\u4ee5\u5206\u5272\u5168\u90e8\u4e09\u89d2\u5f62\u7684line segment<\/div>\n<\/li>\n
  1128. \n
     <\/div>\n<\/li>\n
  1129. \n
    (<\/span>\u63d0\u793a: repeat,<\/span> np.roll<\/span>,<\/span> np.sort<\/span>,<\/span> view,<\/span> np.unique<\/span>)<\/span><\/div>\n<\/li>\n
  1130. \n
     <\/div>\n<\/li>\n
  1131. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1132. \n
     <\/div>\n<\/li>\n
  1133. \n
    # faces = np.random.randint(0,100,(10,3))<\/span><\/div>\n<\/li>\n
  1134. \n
     <\/div>\n<\/li>\n
  1135. \n
    # F = np.roll(faces.repeat(2,axis=1),-1,axis=1)<\/span><\/div>\n<\/li>\n
  1136. \n
     <\/div>\n<\/li>\n
  1137. \n
    # F = F.reshape(len(F)*3,2)<\/span><\/div>\n<\/li>\n
  1138. \n
     <\/div>\n<\/li>\n
  1139. \n
    # F = np.sort(F,axis=1)<\/span><\/div>\n<\/li>\n
  1140. \n
     <\/div>\n<\/li>\n
  1141. \n
    # G = F.view( dtype=[(‘p0’,F.dtype),(‘p1’,F.dtype)] )<\/span><\/div>\n<\/li>\n
  1142. \n
     <\/div>\n<\/li>\n
  1143. \n
    # G = np.unique(G)<\/span><\/div>\n<\/li>\n
  1144. \n
     <\/div>\n<\/li>\n
  1145. \n
    # print (G)<\/span><\/div>\n<\/li>\n
  1146. \n
     <\/div>\n<\/li>\n
  1147. \n
    74<\/span>. \u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u8fdb\u5236\u7684\u6570\u7ec4C\uff0c\u5982\u4f55\u4ea7\u751f\u4e00\u4e2a\u6570\u7ec4A\u6ee1\u8db3np.bincount<\/span>(<\/span>A)<\/span>==<\/span>C<\/div>\n<\/li>\n
  1148. \n
     <\/div>\n<\/li>\n
  1149. \n
    (<\/span>\u63d0\u793a: np.repeat<\/span>)<\/span><\/div>\n<\/li>\n
  1150. \n
     <\/div>\n<\/li>\n
  1151. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1152. \n
     <\/div>\n<\/li>\n
  1153. \n
    # C = np.bincount([1,1,2,3,4,4,6])<\/span><\/div>\n<\/li>\n
  1154. \n
     <\/div>\n<\/li>\n
  1155. \n
    # A = np.repeat(np.arange(len(C)), C)<\/span><\/div>\n<\/li>\n
  1156. \n
     <\/div>\n<\/li>\n
  1157. \n
    # print (A)<\/span><\/div>\n<\/li>\n
  1158. \n
     <\/div>\n<\/li>\n
  1159. \n
    75<\/span>. \u5982\u4f55\u901a\u8fc7\u6ed1\u52a8\u7a97\u53e3\u8ba1\u7b97\u4e00\u4e2a\u6570\u7ec4\u7684\u5e73\u5747\u6570?<\/div>\n<\/li>\n
  1160. \n
     <\/div>\n<\/li>\n
  1161. \n
    (<\/span>\u63d0\u793a: np.cumsum<\/span>)<\/span><\/div>\n<\/li>\n
  1162. \n
     <\/div>\n<\/li>\n
  1163. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1164. \n
     <\/div>\n<\/li>\n
  1165. \n
    # def moving_average(a, n=3) :<\/span><\/div>\n<\/li>\n
  1166. \n
     <\/div>\n<\/li>\n
  1167. \n
    # ret = np.cumsum(a, dtype=float)<\/span><\/div>\n<\/li>\n
  1168. \n
     <\/div>\n<\/li>\n
  1169. \n
    # ret[n:] = ret[n:] – ret[:-n]<\/span><\/div>\n<\/li>\n
  1170. \n
     <\/div>\n<\/li>\n
  1171. \n
    # return ret[n – 1:] \/ n<\/span><\/div>\n<\/li>\n
  1172. \n
     <\/div>\n<\/li>\n
  1173. \n
    # Z = np.arange(20)<\/span><\/div>\n<\/li>\n
  1174. \n
     <\/div>\n<\/li>\n
  1175. \n
    # print(moving_average(Z, n=3))<\/span><\/div>\n<\/li>\n
  1176. \n
     <\/div>\n<\/li>\n
  1177. \n
    76<\/span>. \u8003\u8651\u4e00\u7ef4\u6570\u7ec4Z\uff0c\u6784\u5efa\u4e00\u4e2a\u4e8c\u7ef4\u6570\u7ec4\uff0c\u5176\u7b2c\u4e00\u884c\u662f\uff08Z [<\/span>0<\/span>]<\/span>\uff0cZ [<\/span>1<\/span>]<\/span>\uff0cZ [<\/span>2<\/span>]<\/span>\uff09\uff0c\u6bcf\u4e2a\u540e\u7eed\u884c\u79fb1<\/span>\uff08\u6700\u540e\u4e00\u884c\u5e94\u8be5\u662f\uff08 Z [<\/span>–3<\/span>]<\/span>\uff0cZ [<\/span>–2<\/span>]<\/span>\uff0cZ [<\/span>–1<\/span>]<\/span>\uff09<\/div>\n<\/li>\n
  1178. \n
     <\/div>\n<\/li>\n
  1179. \n
    (<\/span>\u63d0\u793a: from<\/span> numpy.lib<\/span> import<\/span> stride_tricks)<\/span><\/div>\n<\/li>\n
  1180. \n
     <\/div>\n<\/li>\n
  1181. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1182. \n
     <\/div>\n<\/li>\n
  1183. \n
    # from numpy.lib import stride_tricks<\/span><\/div>\n<\/li>\n
  1184. \n
     <\/div>\n<\/li>\n
  1185. \n
    # def rolling(a, window):<\/span><\/div>\n<\/li>\n
  1186. \n
     <\/div>\n<\/li>\n
  1187. \n
    # shape = (a.size – window + 1, window)<\/span><\/div>\n<\/li>\n
  1188. \n
     <\/div>\n<\/li>\n
  1189. \n
    # strides = (a.itemsize, a.itemsize)<\/span><\/div>\n<\/li>\n
  1190. \n
     <\/div>\n<\/li>\n
  1191. \n
    # return stride_tricks.as_strided(a, shape=shape, strides=strides)<\/span><\/div>\n<\/li>\n
  1192. \n
     <\/div>\n<\/li>\n
  1193. \n
    # Z = rolling(np.arange(10), 3)<\/span><\/div>\n<\/li>\n
  1194. \n
     <\/div>\n<\/li>\n
  1195. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  1196. \n
     <\/div>\n<\/li>\n
  1197. \n
    77<\/span>. \u5982\u4f55\u5bf9\u5e03\u5c14\u503c\u53d6\u53cd\uff0c\u6216\u8005\u539f\u4f4d(<\/span>in-place)<\/span>\u6539\u53d8\u6d6e\u70b9\u6570\u7684\u7b26\u53f7(<\/span>sign)<\/span>\uff1f<\/div>\n<\/li>\n
  1198. \n
     <\/div>\n<\/li>\n
  1199. \n
    (<\/span>\u63d0\u793a: np.logical_not<\/span>,<\/span> np.negative<\/span>)<\/span><\/div>\n<\/li>\n
  1200. \n
     <\/div>\n<\/li>\n
  1201. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1202. \n
     <\/div>\n<\/li>\n
  1203. \n
    # Z = np.random.randint(0,2,100)<\/span><\/div>\n<\/li>\n
  1204. \n
     <\/div>\n<\/li>\n
  1205. \n
    # np.logical_not(Z, out=Z)<\/span><\/div>\n<\/li>\n
  1206. \n
     <\/div>\n<\/li>\n
  1207. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1208. \n
     <\/div>\n<\/li>\n
  1209. \n
    # Z = np.random.uniform(-1.0,1.0,100)<\/span><\/div>\n<\/li>\n
  1210. \n
     <\/div>\n<\/li>\n
  1211. \n
    # np.negative(Z, out=Z)<\/span><\/div>\n<\/li>\n
  1212. \n
     <\/div>\n<\/li>\n
  1213. \n
    78<\/span>. \u8003\u8651\u4e24\u7ec4\u70b9\u96c6P0\u548cP1\u53bb\u63cf\u8ff0\u4e00\u7ec4\u7ebf(<\/span>\u4e8c\u7ef4)<\/span>\u548c\u4e00\u4e2a\u70b9p,<\/span>\u5982\u4f55\u8ba1\u7b97\u70b9p\u5230\u6bcf\u4e00\u6761\u7ebf i (<\/span>P0[<\/span>i]<\/span>,<\/span>P1[<\/span>i]<\/span>)<\/span>\u7684\u8ddd\u79bb\uff1f<\/div>\n<\/li>\n
  1214. \n
     <\/div>\n<\/li>\n
  1215. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1216. \n
     <\/div>\n<\/li>\n
  1217. \n
    # def distance(P0, P1, p):<\/span><\/div>\n<\/li>\n
  1218. \n
     <\/div>\n<\/li>\n
  1219. \n
    # T = P1 – P0<\/span><\/div>\n<\/li>\n
  1220. \n
     <\/div>\n<\/li>\n
  1221. \n
    # L = (T**2).sum(axis=1)<\/span><\/div>\n<\/li>\n
  1222. \n
     <\/div>\n<\/li>\n
  1223. \n
    # U = -((P0[:,0]-p[…,0])*T[:,0] + (P0[:,1]-p[…,1])*T[:,1]) \/ L<\/span><\/div>\n<\/li>\n
  1224. \n
     <\/div>\n<\/li>\n
  1225. \n
    # U = U.reshape(len(U),1)<\/span><\/div>\n<\/li>\n
  1226. \n
     <\/div>\n<\/li>\n
  1227. \n
    # D = P0 + U*T – p<\/span><\/div>\n<\/li>\n
  1228. \n
     <\/div>\n<\/li>\n
  1229. \n
    # return np.sqrt((D**2).sum(axis=1))<\/span><\/div>\n<\/li>\n
  1230. \n
     <\/div>\n<\/li>\n
  1231. \n
    # P0 = np.random.uniform(-10,10,(10,2))<\/span><\/div>\n<\/li>\n
  1232. \n
     <\/div>\n<\/li>\n
  1233. \n
    # P1 = np.random.uniform(-10,10,(10,2))<\/span><\/div>\n<\/li>\n
  1234. \n
     <\/div>\n<\/li>\n
  1235. \n
    # p = np.random.uniform(-10,10,( 1,2))<\/span><\/div>\n<\/li>\n
  1236. \n
     <\/div>\n<\/li>\n
  1237. \n
    # print (distance(P0, P1, p))<\/span><\/div>\n<\/li>\n
  1238. \n
     <\/div>\n<\/li>\n
  1239. \n
    79<\/span>.\u8003\u8651\u4e24\u7ec4\u70b9\u96c6P0\u548cP1\u53bb\u63cf\u8ff0\u4e00\u7ec4\u7ebf(<\/span>\u4e8c\u7ef4)<\/span>\u548c\u4e00\u7ec4\u70b9\u96c6P\uff0c\u5982\u4f55\u8ba1\u7b97\u6bcf\u4e00\u4e2a\u70b9 j(<\/span>P[<\/span>j]<\/span>)<\/span> \u5230\u6bcf\u4e00\u6761\u7ebf i (<\/span>P0[<\/span>i]<\/span>,<\/span>P1[<\/span>i]<\/span>)<\/span>\u7684\u8ddd\u79bb\uff1f<\/div>\n<\/li>\n
  1240. \n
     <\/div>\n<\/li>\n
  1241. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1242. \n
     <\/div>\n<\/li>\n
  1243. \n
    # # based on distance function from previous question<\/span><\/div>\n<\/li>\n
  1244. \n
     <\/div>\n<\/li>\n
  1245. \n
    # P0 = np.random.uniform(-10, 10, (10,2))<\/span><\/div>\n<\/li>\n
  1246. \n
     <\/div>\n<\/li>\n
  1247. \n
    # P1 = np.random.uniform(-10,10,(10,2))<\/span><\/div>\n<\/li>\n
  1248. \n
     <\/div>\n<\/li>\n
  1249. \n
    # p = np.random.uniform(-10, 10, (10,2))<\/span><\/div>\n<\/li>\n
  1250. \n
     <\/div>\n<\/li>\n
  1251. \n
    # print (np.array([distance(P0,P1,p_i) for p_i in p]))<\/span><\/div>\n<\/li>\n
  1252. \n
     <\/div>\n<\/li>\n
  1253. \n
    80<\/span>.\u8003\u8651\u4e00\u4e2a\u4efb\u610f\u6570\u7ec4\uff0c\u5199\u4e00\u4e2a\u51fd\u6570\uff0c\u63d0\u53d6\u4e00\u4e2a\u56fa\u5b9a\u5f62\u72b6\u7684\u5b50\u90e8\u5206\uff0c\u5e76\u4ee5\u7ed9\u5b9a\u5143\u7d20\u4e3a\u4e2d\u5fc3\uff08fill\u5fc5\u8981\u65f6\u586b\u5145\u4e00\u4e2a\u503c\uff09<\/div>\n<\/li>\n
  1254. \n
     <\/div>\n<\/li>\n
  1255. \n
    (<\/span>\u63d0\u793a: minimum,<\/span> maximum)<\/span><\/div>\n<\/li>\n
  1256. \n
     <\/div>\n<\/li>\n
  1257. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1258. \n
     <\/div>\n<\/li>\n
  1259. \n
    # Z = np.random.randint(0,10,(10,10))<\/span><\/div>\n<\/li>\n
  1260. \n
     <\/div>\n<\/li>\n
  1261. \n
    # shape = (5,5)<\/span><\/div>\n<\/li>\n
  1262. \n
     <\/div>\n<\/li>\n
  1263. \n
    # fill = 0<\/span><\/div>\n<\/li>\n
  1264. \n
     <\/div>\n<\/li>\n
  1265. \n
    # position = (1,1)<\/span><\/div>\n<\/li>\n
  1266. \n
     <\/div>\n<\/li>\n
  1267. \n
    # R = np.ones(shape, dtype=Z.dtype)*fill<\/span><\/div>\n<\/li>\n
  1268. \n
     <\/div>\n<\/li>\n
  1269. \n
    # P = np.array(list(position)).astype(int)<\/span><\/div>\n<\/li>\n
  1270. \n
     <\/div>\n<\/li>\n
  1271. \n
    # Rs = np.array(list(R.shape)).astype(int)<\/span><\/div>\n<\/li>\n
  1272. \n
     <\/div>\n<\/li>\n
  1273. \n
    # Zs = np.array(list(Z.shape)).astype(int)<\/span><\/div>\n<\/li>\n
  1274. \n
     <\/div>\n<\/li>\n
  1275. \n
    # R_start = np.zeros((len(shape),)).astype(int)<\/span><\/div>\n<\/li>\n
  1276. \n
     <\/div>\n<\/li>\n
  1277. \n
    # R_stop = np.array(list(shape)).astype(int)<\/span><\/div>\n<\/li>\n
  1278. \n
     <\/div>\n<\/li>\n
  1279. \n
    # Z_start = (P-Rs\/\/2)<\/span><\/div>\n<\/li>\n
  1280. \n
     <\/div>\n<\/li>\n
  1281. \n
    # Z_stop = (P+Rs\/\/2)+Rs%2<\/span><\/div>\n<\/li>\n
  1282. \n
     <\/div>\n<\/li>\n
  1283. \n
    # R_start = (R_start – np.minimum(Z_start,0)).tolist()<\/span><\/div>\n<\/li>\n
  1284. \n
     <\/div>\n<\/li>\n
  1285. \n
    # Z_start = (np.maximum(Z_start,0)).tolist()<\/span><\/div>\n<\/li>\n
  1286. \n
     <\/div>\n<\/li>\n
  1287. \n
    # R_stop = np.maximum(R_start, (R_stop – np.maximum(Z_stop-Zs,0))).tolist()<\/span><\/div>\n<\/li>\n
  1288. \n
     <\/div>\n<\/li>\n
  1289. \n
    # Z_stop = (np.minimum(Z_stop,Zs)).tolist()<\/span><\/div>\n<\/li>\n
  1290. \n
     <\/div>\n<\/li>\n
  1291. \n
    # r = [slice(start,stop) for start,stop in zip(R_start,R_stop)]<\/span><\/div>\n<\/li>\n
  1292. \n
     <\/div>\n<\/li>\n
  1293. \n
    # z = [slice(start,stop) for start,stop in zip(Z_start,Z_stop)]<\/span><\/div>\n<\/li>\n
  1294. \n
     <\/div>\n<\/li>\n
  1295. \n
    # R[r] = Z[z]<\/span><\/div>\n<\/li>\n
  1296. \n
     <\/div>\n<\/li>\n
  1297. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  1298. \n
     <\/div>\n<\/li>\n
  1299. \n
    # print (R)<\/span><\/div>\n<\/li>\n
  1300. \n
     <\/div>\n<\/li>\n
  1301. \n
    81<\/span>. \u8003\u8651\u4e00\u4e2a\u6570\u7ec4Z =<\/span> [<\/span>1<\/span>,<\/span>2<\/span>,<\/span>3<\/span>,<\/span>4<\/span>,<\/span>5<\/span>,<\/span>6<\/span>,<\/span>7<\/span>,<\/span>8<\/span>,<\/span>9<\/span>,<\/span>10<\/span>,<\/span>11<\/span>,<\/span>12<\/span>,<\/span>13<\/span>,<\/span>14<\/span>]<\/span>,<\/span>\u5982\u4f55\u751f\u6210\u4e00\u4e2a\u6570\u7ec4R =<\/span> [<\/span>[<\/span>1<\/span>,<\/span>2<\/span>,<\/span>3<\/span>,<\/span>4<\/span>]<\/span>,<\/span> [<\/span>2<\/span>,<\/span>3<\/span>,<\/span>4<\/span>,<\/span>5<\/span>]<\/span>,<\/span> [<\/span>3<\/span>,<\/span>4<\/span>,<\/span>5<\/span>,<\/span>6<\/span>]<\/span>,<\/span> …,<\/span>[<\/span>11<\/span>,<\/span>12<\/span>,<\/span>13<\/span>,<\/span>14<\/span>]<\/span>]<\/span>?<\/div>\n<\/li>\n
  1302. \n
     <\/div>\n<\/li>\n
  1303. \n
    (<\/span>\u63d0\u793a: stride_tricks.as_strided<\/span>)<\/span><\/div>\n<\/li>\n
  1304. \n
     <\/div>\n<\/li>\n
  1305. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1306. \n
     <\/div>\n<\/li>\n
  1307. \n
    # Z = np.arange(1,15,dtype=np.uint32)<\/span><\/div>\n<\/li>\n
  1308. \n
     <\/div>\n<\/li>\n
  1309. \n
    # R = stride_tricks.as_strided(Z,(11,4),(4,4))<\/span><\/div>\n<\/li>\n
  1310. \n
     <\/div>\n<\/li>\n
  1311. \n
    # print (R)<\/span><\/div>\n<\/li>\n
  1312. \n
     <\/div>\n<\/li>\n
  1313. \n
    82<\/span>. \u8ba1\u7b97\u4e00\u4e2a\u77e9\u9635\u7684\u79e9<\/div>\n<\/li>\n
  1314. \n
     <\/div>\n<\/li>\n
  1315. \n
    (<\/span>\u63d0\u793a: np.linalg<\/span>.svd<\/span>)<\/span><\/div>\n<\/li>\n
  1316. \n
     <\/div>\n<\/li>\n
  1317. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1318. \n
     <\/div>\n<\/li>\n
  1319. \n
    # Z = np.random.uniform(0,1,(10,10))<\/span><\/div>\n<\/li>\n
  1320. \n
     <\/div>\n<\/li>\n
  1321. \n
    # U, S, V = np.linalg.svd(Z) # Singular Value Decomposition<\/span><\/div>\n<\/li>\n
  1322. \n
     <\/div>\n<\/li>\n
  1323. \n
    # rank = np.sum(S > 1e-10)<\/span><\/div>\n<\/li>\n
  1324. \n
     <\/div>\n<\/li>\n
  1325. \n
    # print (rank)<\/span><\/div>\n<\/li>\n
  1326. \n
     <\/div>\n<\/li>\n
  1327. \n
    83<\/span>. \u5982\u4f55\u627e\u5230\u4e00\u4e2a\u6570\u7ec4\u4e2d\u51fa\u73b0\u9891\u7387\u6700\u9ad8\u7684\u503c\uff1f<\/div>\n<\/li>\n
  1328. \n
     <\/div>\n<\/li>\n
  1329. \n
    (<\/span>\u63d0\u793a: np.bincount<\/span>,<\/span> argmax)<\/span><\/div>\n<\/li>\n
  1330. \n
     <\/div>\n<\/li>\n
  1331. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1332. \n
     <\/div>\n<\/li>\n
  1333. \n
    # Z = np.random.randint(0,10,50)<\/span><\/div>\n<\/li>\n
  1334. \n
     <\/div>\n<\/li>\n
  1335. \n
    # print (np.bincount(Z).argmax())<\/span><\/div>\n<\/li>\n
  1336. \n
     <\/div>\n<\/li>\n
  1337. \n
    84<\/span>. \u4ece\u4e00\u4e2a10×10\u7684\u77e9\u9635\u4e2d\u63d0\u53d6\u51fa\u8fde\u7eed\u76843×3\u533a\u5757<\/div>\n<\/li>\n
  1338. \n
     <\/div>\n<\/li>\n
  1339. \n
    (<\/span>\u63d0\u793a: stride_tricks.as_strided<\/span>)<\/span><\/div>\n<\/li>\n
  1340. \n
     <\/div>\n<\/li>\n
  1341. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1342. \n
     <\/div>\n<\/li>\n
  1343. \n
    # Z = np.random.randint(0,5,(10,10))<\/span><\/div>\n<\/li>\n
  1344. \n
     <\/div>\n<\/li>\n
  1345. \n
    # n = 3<\/span><\/div>\n<\/li>\n
  1346. \n
     <\/div>\n<\/li>\n
  1347. \n
    # i = 1 + (Z.shape[0]-3)<\/span><\/div>\n<\/li>\n
  1348. \n
     <\/div>\n<\/li>\n
  1349. \n
    # j = 1 + (Z.shape[1]-3)<\/span><\/div>\n<\/li>\n
  1350. \n
     <\/div>\n<\/li>\n
  1351. \n
    # C = stride_tricks.as_strided(Z, shape=(i, j, n, n), strides=Z.strides + Z.strides)<\/span><\/div>\n<\/li>\n
  1352. \n
     <\/div>\n<\/li>\n
  1353. \n
    # print (C)<\/span><\/div>\n<\/li>\n
  1354. \n
     <\/div>\n<\/li>\n
  1355. \n
    85<\/span>. \u521b\u5efa\u4e00\u4e2a\u6ee1\u8db3 Z[<\/span>i,<\/span>j]<\/span> ==<\/span> Z[<\/span>j,<\/span>i]<\/span>\u7684\u5b50\u7c7b<\/div>\n<\/li>\n
  1356. \n
     <\/div>\n<\/li>\n
  1357. \n
    (<\/span>\u63d0\u793a: class<\/span> \u65b9\u6cd5)<\/span><\/div>\n<\/li>\n
  1358. \n
     <\/div>\n<\/li>\n
  1359. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1360. \n
     <\/div>\n<\/li>\n
  1361. \n
    # class Symetric(np.ndarray):<\/span><\/div>\n<\/li>\n
  1362. \n
     <\/div>\n<\/li>\n
  1363. \n
    # def __setitem__(self, index, value):<\/span><\/div>\n<\/li>\n
  1364. \n
     <\/div>\n<\/li>\n
  1365. \n
    # i,j = index<\/span><\/div>\n<\/li>\n
  1366. \n
     <\/div>\n<\/li>\n
  1367. \n
    # super(Symetric, self).__setitem__((i,j), value)<\/span><\/div>\n<\/li>\n
  1368. \n
     <\/div>\n<\/li>\n
  1369. \n
    # super(Symetric, self).__setitem__((j,i), value)<\/span><\/div>\n<\/li>\n
  1370. \n
     <\/div>\n<\/li>\n
  1371. \n
    # def symetric(Z):<\/span><\/div>\n<\/li>\n
  1372. \n
     <\/div>\n<\/li>\n
  1373. \n
    # return np.asarray(Z + Z.T – np.diag(Z.diagonal())).view(Symetric)<\/span><\/div>\n<\/li>\n
  1374. \n
     <\/div>\n<\/li>\n
  1375. \n
    # S = symetric(np.random.randint(0,10,(5,5)))<\/span><\/div>\n<\/li>\n
  1376. \n
     <\/div>\n<\/li>\n
  1377. \n
    # S[2,3] = 42<\/span><\/div>\n<\/li>\n
  1378. \n
     <\/div>\n<\/li>\n
  1379. \n
    # print (S)<\/span><\/div>\n<\/li>\n
  1380. \n
     <\/div>\n<\/li>\n
  1381. \n
    86<\/span>. \u8003\u8651p\u4e2a nxn \u77e9\u9635\u548c\u4e00\u7ec4\u5f62\u72b6\u4e3a(<\/span>n,<\/span>1<\/span>)<\/span>\u7684\u5411\u91cf\uff0c\u5982\u4f55\u76f4\u63a5\u8ba1\u7b97p\u4e2a\u77e9\u9635\u7684\u4e58\u79ef(<\/span>n,<\/span>1<\/span>)<\/span>\uff1f<\/div>\n<\/li>\n
  1382. \n
     <\/div>\n<\/li>\n
  1383. \n
    (<\/span>\u63d0\u793a: np.tensordot<\/span>)<\/span><\/div>\n<\/li>\n
  1384. \n
     <\/div>\n<\/li>\n
  1385. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1386. \n
     <\/div>\n<\/li>\n
  1387. \n
    # p, n = 10, 20<\/span><\/div>\n<\/li>\n
  1388. \n
     <\/div>\n<\/li>\n
  1389. \n
    # M = np.ones((p,n,n))<\/span><\/div>\n<\/li>\n
  1390. \n
     <\/div>\n<\/li>\n
  1391. \n
    # V = np.ones((p,n,1))<\/span><\/div>\n<\/li>\n
  1392. \n
     <\/div>\n<\/li>\n
  1393. \n
    # S = np.tensordot(M, V, axes=[[0, 2], [0, 1]])<\/span><\/div>\n<\/li>\n
  1394. \n
     <\/div>\n<\/li>\n
  1395. \n
    # print (S)<\/span><\/div>\n<\/li>\n
  1396. \n
     <\/div>\n<\/li>\n
  1397. \n
    # It works, because:<\/span><\/div>\n<\/li>\n
  1398. \n
     <\/div>\n<\/li>\n
  1399. \n
    # M is (p,n,n)<\/span><\/div>\n<\/li>\n
  1400. \n
     <\/div>\n<\/li>\n
  1401. \n
    # V is (p,n,1)<\/span><\/div>\n<\/li>\n
  1402. \n
     <\/div>\n<\/li>\n
  1403. \n
    # Thus, summing over the paired axes 0 and 0 (of M and V independently),<\/span><\/div>\n<\/li>\n
  1404. \n
     <\/div>\n<\/li>\n
  1405. \n
    # and 2 and 1, to remain with a (n,1) vector.<\/span><\/div>\n<\/li>\n
  1406. \n
     <\/div>\n<\/li>\n
  1407. \n
    87<\/span>. \u5bf9\u4e8e\u4e00\u4e2a16×16\u7684\u6570\u7ec4\uff0c\u5982\u4f55\u5f97\u5230\u4e00\u4e2a\u533a\u57df(<\/span>block-sum<\/span>)<\/span>\u7684\u548c(<\/span>\u533a\u57df\u5927\u5c0f\u4e3a4×4)<\/span>?<\/div>\n<\/li>\n
  1408. \n
     <\/div>\n<\/li>\n
  1409. \n
    (<\/span>\u63d0\u793a: np.add<\/span>.reduceat<\/span>)<\/span><\/div>\n<\/li>\n
  1410. \n
     <\/div>\n<\/li>\n
  1411. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1412. \n
     <\/div>\n<\/li>\n
  1413. \n
    # Z = np.ones((16,16))<\/span><\/div>\n<\/li>\n
  1414. \n
     <\/div>\n<\/li>\n
  1415. \n
    # k = 4<\/span><\/div>\n<\/li>\n
  1416. \n
     <\/div>\n<\/li>\n
  1417. \n
    # S = np.add.reduceat(np.add.reduceat(Z, np.arange(0, Z.shape[0], k), axis=0),<\/span><\/div>\n<\/li>\n
  1418. \n
     <\/div>\n<\/li>\n
  1419. \n
    # np.arange(0, Z.shape[1], k), axis=1)<\/span><\/div>\n<\/li>\n
  1420. \n
     <\/div>\n<\/li>\n
  1421. \n
    # print (S)<\/span><\/div>\n<\/li>\n
  1422. \n
     <\/div>\n<\/li>\n
  1423. \n
    88<\/span>. \u5982\u4f55\u5229\u7528numpy\u6570\u7ec4\u5b9e\u73b0Game of Life?<\/div>\n<\/li>\n
  1424. \n
     <\/div>\n<\/li>\n
  1425. \n
    (<\/span>\u63d0\u793a: Game of Life)<\/span><\/div>\n<\/li>\n
  1426. \n
     <\/div>\n<\/li>\n
  1427. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1428. \n
     <\/div>\n<\/li>\n
  1429. \n
    # def iterate(Z):<\/span><\/div>\n<\/li>\n
  1430. \n
     <\/div>\n<\/li>\n
  1431. \n
    # # Count neighbours<\/span><\/div>\n<\/li>\n
  1432. \n
     <\/div>\n<\/li>\n
  1433. \n
    # N = (Z[0:-2,0:-2] + Z[0:-2,1:-1] + Z[0:-2,2:] +<\/span><\/div>\n<\/li>\n
  1434. \n
     <\/div>\n<\/li>\n
  1435. \n
    # Z[1:-1,0:-2] + Z[1:-1,2:] +<\/span><\/div>\n<\/li>\n
  1436. \n
     <\/div>\n<\/li>\n
  1437. \n
    # Z[2: ,0:-2] + Z[2: ,1:-1] + Z[2: ,2:])<\/span><\/div>\n<\/li>\n
  1438. \n
     <\/div>\n<\/li>\n
  1439. \n
    # # Apply rules<\/span><\/div>\n<\/li>\n
  1440. \n
     <\/div>\n<\/li>\n
  1441. \n
    # birth = (N==3) & (Z[1:-1,1:-1]==0)<\/span><\/div>\n<\/li>\n
  1442. \n
     <\/div>\n<\/li>\n
  1443. \n
    # survive = ((N==2) | (N==3)) & (Z[1:-1,1:-1]==1)<\/span><\/div>\n<\/li>\n
  1444. \n
     <\/div>\n<\/li>\n
  1445. \n
    # Z[…] = 0<\/span><\/div>\n<\/li>\n
  1446. \n
     <\/div>\n<\/li>\n
  1447. \n
    # Z[1:-1,1:-1][birth | survive] = 1<\/span><\/div>\n<\/li>\n
  1448. \n
     <\/div>\n<\/li>\n
  1449. \n
    # return Z<\/span><\/div>\n<\/li>\n
  1450. \n
     <\/div>\n<\/li>\n
  1451. \n
    # Z = np.random.randint(0,2,(50,50))<\/span><\/div>\n<\/li>\n
  1452. \n
     <\/div>\n<\/li>\n
  1453. \n
    # for i in range(100): Z = iterate(Z)<\/span><\/div>\n<\/li>\n
  1454. \n
     <\/div>\n<\/li>\n
  1455. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  1456. \n
     <\/div>\n<\/li>\n
  1457. \n
    89<\/span>. \u5982\u4f55\u627e\u5230\u4e00\u4e2a\u6570\u7ec4\u7684\u7b2cn\u4e2a\u6700\u5927\u503c?<\/div>\n<\/li>\n
  1458. \n
     <\/div>\n<\/li>\n
  1459. \n
    (<\/span>\u63d0\u793a: np.argsort<\/span> | np.argpartition<\/span>)<\/span><\/div>\n<\/li>\n
  1460. \n
     <\/div>\n<\/li>\n
  1461. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1462. \n
     <\/div>\n<\/li>\n
  1463. \n
    # Z = np.arange(10000)<\/span><\/div>\n<\/li>\n
  1464. \n
     <\/div>\n<\/li>\n
  1465. \n
    # np.random.shuffle(Z)<\/span><\/div>\n<\/li>\n
  1466. \n
     <\/div>\n<\/li>\n
  1467. \n
    # n = 5<\/span><\/div>\n<\/li>\n
  1468. \n
     <\/div>\n<\/li>\n
  1469. \n
    # # Slow<\/span><\/div>\n<\/li>\n
  1470. \n
     <\/div>\n<\/li>\n
  1471. \n
    # print (Z[np.argsort(Z)[-n:]])<\/span><\/div>\n<\/li>\n
  1472. \n
     <\/div>\n<\/li>\n
  1473. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1474. \n
     <\/div>\n<\/li>\n
  1475. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  1476. \n
     <\/div>\n<\/li>\n
  1477. \n
    # # Fast<\/span><\/div>\n<\/li>\n
  1478. \n
     <\/div>\n<\/li>\n
  1479. \n
    # print (Z[np.argpartition(-Z,n)[:n]])<\/span><\/div>\n<\/li>\n
  1480. \n
     <\/div>\n<\/li>\n
  1481. \n
    90<\/span>. \u7ed9\u5b9a\u4efb\u610f\u4e2a\u6570\u5411\u91cf\uff0c\u521b\u5efa\u7b1b\u5361\u5c14\u79ef(<\/span>\u6bcf\u4e00\u4e2a\u5143\u7d20\u7684\u6bcf\u4e00\u79cd\u7ec4\u5408)<\/span><\/div>\n<\/li>\n
  1482. \n
     <\/div>\n<\/li>\n
  1483. \n
    (<\/span>\u63d0\u793a: np.indices<\/span>)<\/span><\/div>\n<\/li>\n
  1484. \n
     <\/div>\n<\/li>\n
  1485. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1486. \n
     <\/div>\n<\/li>\n
  1487. \n
    # def cartesian(arrays):<\/span><\/div>\n<\/li>\n
  1488. \n
     <\/div>\n<\/li>\n
  1489. \n
    # arrays = [np.asarray(a) for a in arrays]<\/span><\/div>\n<\/li>\n
  1490. \n
     <\/div>\n<\/li>\n
  1491. \n
    # shape = (len(x) for x in arrays)<\/span><\/div>\n<\/li>\n
  1492. \n
     <\/div>\n<\/li>\n
  1493. \n
    # ix = np.indices(shape, dtype=int)<\/span><\/div>\n<\/li>\n
  1494. \n
     <\/div>\n<\/li>\n
  1495. \n
    # ix = ix.reshape(len(arrays), -1).T<\/span><\/div>\n<\/li>\n
  1496. \n
     <\/div>\n<\/li>\n
  1497. \n
    # for n, arr in enumerate(arrays):<\/span><\/div>\n<\/li>\n
  1498. \n
     <\/div>\n<\/li>\n
  1499. \n
    # ix[:, n] = arrays[n][ix[:, n]]<\/span><\/div>\n<\/li>\n
  1500. \n
     <\/div>\n<\/li>\n
  1501. \n
    # return ix<\/span><\/div>\n<\/li>\n
  1502. \n
     <\/div>\n<\/li>\n
  1503. \n
    # print (cartesian(([1, 2, 3], [4, 5], [6, 7])))<\/span><\/div>\n<\/li>\n
  1504. \n
     <\/div>\n<\/li>\n
  1505. \n
    91<\/span>. \u5982\u4f55\u4ece\u4e00\u4e2a\u6b63\u5e38\u6570\u7ec4\u521b\u5efa\u8bb0\u5f55\u6570\u7ec4(<\/span>record array<\/span>)<\/span>?<\/div>\n<\/li>\n
  1506. \n
     <\/div>\n<\/li>\n
  1507. \n
    (<\/span>\u63d0\u793a: np.core<\/span>.records<\/span>.fromarrays<\/span>)<\/span><\/div>\n<\/li>\n
  1508. \n
     <\/div>\n<\/li>\n
  1509. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1510. \n
     <\/div>\n<\/li>\n
  1511. \n
    # Z = np.array([("Hello", 2.5, 3),<\/span><\/div>\n<\/li>\n
  1512. \n
     <\/div>\n<\/li>\n
  1513. \n
    # ("World", 3.6, 2)])<\/span><\/div>\n<\/li>\n
  1514. \n
     <\/div>\n<\/li>\n
  1515. \n
    # R = np.core.records.fromarrays(Z.T,<\/span><\/div>\n<\/li>\n
  1516. \n
     <\/div>\n<\/li>\n
  1517. \n
    # names=’col1, col2, col3′,<\/span><\/div>\n<\/li>\n
  1518. \n
     <\/div>\n<\/li>\n
  1519. \n
    # formats = ‘S8, f8, i8’)<\/span><\/div>\n<\/li>\n
  1520. \n
     <\/div>\n<\/li>\n
  1521. \n
    # print (R)<\/span><\/div>\n<\/li>\n
  1522. \n
     <\/div>\n<\/li>\n
  1523. \n
    92<\/span>. \u8003\u8651\u4e00\u4e2a\u5927\u5411\u91cfZ,<\/span> \u7528\u4e09\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\u8ba1\u7b97\u5b83\u7684\u7acb\u65b9<\/div>\n<\/li>\n
  1524. \n
     <\/div>\n<\/li>\n
  1525. \n
    (<\/span>\u63d0\u793a: np.power<\/span>,<\/span> \\*,<\/span> np.einsum<\/span>)<\/span><\/div>\n<\/li>\n
  1526. \n
     <\/div>\n<\/li>\n
  1527. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1528. \n
     <\/div>\n<\/li>\n
  1529. \n
    # x = np.random.rand()<\/span><\/div>\n<\/li>\n
  1530. \n
     <\/div>\n<\/li>\n
  1531. \n
    # np.power(x,3)<\/span><\/div>\n<\/li>\n
  1532. \n
     <\/div>\n<\/li>\n
  1533. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1534. \n
     <\/div>\n<\/li>\n
  1535. \n
    ## \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  1536. \n
     <\/div>\n<\/li>\n
  1537. \n
    # x*x*x<\/span><\/div>\n<\/li>\n
  1538. \n
     <\/div>\n<\/li>\n
  1539. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1540. \n
     <\/div>\n<\/li>\n
  1541. \n
    ## \u65b9\u6cd53<\/span><\/div>\n<\/li>\n
  1542. \n
     <\/div>\n<\/li>\n
  1543. \n
    # np.einsum(‘i,i,i->i’,x,x,x)<\/span><\/div>\n<\/li>\n
  1544. \n
     <\/div>\n<\/li>\n
  1545. \n
    93<\/span>. \u8003\u8651\u4e24\u4e2a\u5f62\u72b6\u5206\u522b\u4e3a(<\/span>8<\/span>,<\/span>3<\/span>)<\/span> \u548c(<\/span>2<\/span>,<\/span>2<\/span>)<\/span>\u7684\u6570\u7ec4A\u548cB. \u5982\u4f55\u5728\u6570\u7ec4A\u4e2d\u627e\u5230\u6ee1\u8db3\u5305\u542bB\u4e2d\u5143\u7d20\u7684\u884c\uff1f(<\/span>\u4e0d\u8003\u8651B\u4e2d\u6bcf\u884c\u5143\u7d20\u987a\u5e8f)<\/span>\uff1f<\/div>\n<\/li>\n
  1546. \n
     <\/div>\n<\/li>\n
  1547. \n
    (<\/span>\u63d0\u793a: np.where<\/span>)<\/span><\/div>\n<\/li>\n
  1548. \n
     <\/div>\n<\/li>\n
  1549. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1550. \n
     <\/div>\n<\/li>\n
  1551. \n
    # A = np.random.randint(0,5,(8,3))<\/span><\/div>\n<\/li>\n
  1552. \n
     <\/div>\n<\/li>\n
  1553. \n
    # B = np.random.randint(0,5,(2,2))<\/span><\/div>\n<\/li>\n
  1554. \n
     <\/div>\n<\/li>\n
  1555. \n
    # C = (A[…, np.newaxis, np.newaxis] == B)<\/span><\/div>\n<\/li>\n
  1556. \n
     <\/div>\n<\/li>\n
  1557. \n
    # rows = np.where(C.any((3,1)).all(1))[0]<\/span><\/div>\n<\/li>\n
  1558. \n
     <\/div>\n<\/li>\n
  1559. \n
    # print (rows)<\/span><\/div>\n<\/li>\n
  1560. \n
     <\/div>\n<\/li>\n
  1561. \n
    94<\/span>. \u8003\u8651\u4e00\u4e2a10×3\u7684\u77e9\u9635\uff0c\u5206\u89e3\u51fa\u6709\u4e0d\u5168\u76f8\u540c\u503c\u7684\u884c (<\/span>\u5982 [<\/span>2<\/span>,<\/span>2<\/span>,<\/span>3<\/span>]<\/span>)<\/span><\/div>\n<\/li>\n
  1562. \n
     <\/div>\n<\/li>\n
  1563. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1564. \n
     <\/div>\n<\/li>\n
  1565. \n
    # Z = np.random.randint(0,5,(10,3))<\/span><\/div>\n<\/li>\n
  1566. \n
     <\/div>\n<\/li>\n
  1567. \n
    # print (Z)<\/span><\/div>\n<\/li>\n
  1568. \n
     <\/div>\n<\/li>\n
  1569. \n
    # # solution for arrays of all dtypes (including string arrays and record arrays)<\/span><\/div>\n<\/li>\n
  1570. \n
     <\/div>\n<\/li>\n
  1571. \n
    # E = np.all(Z[:,1:] == Z[:,:-1], axis=1)<\/span><\/div>\n<\/li>\n
  1572. \n
     <\/div>\n<\/li>\n
  1573. \n
    # U = Z[~E]<\/span><\/div>\n<\/li>\n
  1574. \n
     <\/div>\n<\/li>\n
  1575. \n
    # print (U)<\/span><\/div>\n<\/li>\n
  1576. \n
     <\/div>\n<\/li>\n
  1577. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1578. \n
     <\/div>\n<\/li>\n
  1579. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  1580. \n
     <\/div>\n<\/li>\n
  1581. \n
    # # soluiton for numerical arrays only, will work for any number of columns in Z<\/span><\/div>\n<\/li>\n
  1582. \n
     <\/div>\n<\/li>\n
  1583. \n
    # U = Z[Z.max(axis=1) != Z.min(axis=1),:]<\/span><\/div>\n<\/li>\n
  1584. \n
     <\/div>\n<\/li>\n
  1585. \n
    # print (U)<\/span><\/div>\n<\/li>\n
  1586. \n
     <\/div>\n<\/li>\n
  1587. \n
    95<\/span>. \u5c06\u4e00\u4e2a\u6574\u6570\u5411\u91cf\u8f6c\u6362\u4e3amatrix binary\u7684\u8868\u73b0\u5f62\u5f0f<\/div>\n<\/li>\n
  1588. \n
     <\/div>\n<\/li>\n
  1589. \n
    (<\/span>\u63d0\u793a: np.unpackbits<\/span>)<\/span><\/div>\n<\/li>\n
  1590. \n
     <\/div>\n<\/li>\n
  1591. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1592. \n
     <\/div>\n<\/li>\n
  1593. \n
    # I = np.array([0, 1, 2, 3, 15, 16, 32, 64, 128])<\/span><\/div>\n<\/li>\n
  1594. \n
     <\/div>\n<\/li>\n
  1595. \n
    # B = ((I.reshape(-1,1) & (2**np.arange(8))) != 0).astype(int)<\/span><\/div>\n<\/li>\n
  1596. \n
     <\/div>\n<\/li>\n
  1597. \n
    # print(B[:,::-1])<\/span><\/div>\n<\/li>\n
  1598. \n
     <\/div>\n<\/li>\n
  1599. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1600. \n
     <\/div>\n<\/li>\n
  1601. \n
    # # \u65b9\u6cd52<\/span><\/div>\n<\/li>\n
  1602. \n
     <\/div>\n<\/li>\n
  1603. \n
    # print (np.unpackbits(I[:, np.newaxis], axis=1))<\/span><\/div>\n<\/li>\n
  1604. \n
     <\/div>\n<\/li>\n
  1605. \n
    96<\/span>. \u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u7ef4\u6570\u7ec4\uff0c\u5982\u4f55\u63d0\u53d6\u51fa\u552f\u4e00\u7684(<\/span>unique)<\/span>\u884c\uff1f<\/div>\n<\/li>\n
  1606. \n
     <\/div>\n<\/li>\n
  1607. \n
    (<\/span>\u63d0\u793a: np.ascontiguousarray<\/span>)<\/span><\/div>\n<\/li>\n
  1608. \n
     <\/div>\n<\/li>\n
  1609. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1610. \n
     <\/div>\n<\/li>\n
  1611. \n
    # Z = np.random.randint(0,2,(6,3))<\/span><\/div>\n<\/li>\n
  1612. \n
     <\/div>\n<\/li>\n
  1613. \n
    # T = np.ascontiguousarray(Z).view(np.dtype((np.void, Z.dtype.itemsize * Z.shape[1])))<\/span><\/div>\n<\/li>\n
  1614. \n
     <\/div>\n<\/li>\n
  1615. \n
    # _, idx = np.unique(T, return_index=True)<\/span><\/div>\n<\/li>\n
  1616. \n
     <\/div>\n<\/li>\n
  1617. \n
    # uZ = Z[idx]<\/span><\/div>\n<\/li>\n
  1618. \n
     <\/div>\n<\/li>\n
  1619. \n
    # print (uZ)<\/span><\/div>\n<\/li>\n
  1620. \n
     <\/div>\n<\/li>\n
  1621. \n
    97<\/span>. \u8003\u8651\u4e24\u4e2a\u5411\u91cfA\u548cB\uff0c\u5199\u51fa\u7528einsum\u7b49\u5f0f\u5bf9\u5e94\u7684inner,<\/span> outer,<\/span> sum<\/span>,<\/span> mul\u51fd\u6570<\/div>\n<\/li>\n
  1622. \n
     <\/div>\n<\/li>\n
  1623. \n
    (<\/span>\u63d0\u793a: np.einsum<\/span>)<\/span><\/div>\n<\/li>\n
  1624. \n
     <\/div>\n<\/li>\n
  1625. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1626. \n
     <\/div>\n<\/li>\n
  1627. \n
    # A = np.random.uniform(0,1,10)<\/span><\/div>\n<\/li>\n
  1628. \n
     <\/div>\n<\/li>\n
  1629. \n
    # B = np.random.uniform(0,1,10)<\/span><\/div>\n<\/li>\n
  1630. \n
     <\/div>\n<\/li>\n
  1631. \n
    # print (‘sum’)<\/span><\/div>\n<\/li>\n
  1632. \n
     <\/div>\n<\/li>\n
  1633. \n
    # print (np.einsum(‘i->’, A))# np.sum(A)<\/span><\/div>\n<\/li>\n
  1634. \n
     <\/div>\n<\/li>\n
  1635. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1636. \n
     <\/div>\n<\/li>\n
  1637. \n
    # print (‘A * B’)<\/span><\/div>\n<\/li>\n
  1638. \n
     <\/div>\n<\/li>\n
  1639. \n
    # print (np.einsum(‘i,i->i’, A, B)) # A * B<\/span><\/div>\n<\/li>\n
  1640. \n
     <\/div>\n<\/li>\n
  1641. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1642. \n
     <\/div>\n<\/li>\n
  1643. \n
    # print (‘inner’)<\/span><\/div>\n<\/li>\n
  1644. \n
     <\/div>\n<\/li>\n
  1645. \n
    # print (np.einsum(‘i,i’, A, B)) # np.inner(A, B)<\/span><\/div>\n<\/li>\n
  1646. \n
     <\/div>\n<\/li>\n
  1647. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1648. \n
     <\/div>\n<\/li>\n
  1649. \n
    # print (‘outer’)<\/span><\/div>\n<\/li>\n
  1650. \n
     <\/div>\n<\/li>\n
  1651. \n
    # print (np.einsum(‘i,j->ij’, A, B)) # np.outer(A, B)<\/span><\/div>\n<\/li>\n
  1652. \n
     <\/div>\n<\/li>\n
  1653. \n
    98<\/span>. \u8003\u8651\u4e00\u4e2a\u7531\u4e24\u4e2a\u5411\u91cf\u63cf\u8ff0\u7684\u8def\u5f84(<\/span>X,<\/span>Y)<\/span>\uff0c\u5982\u4f55\u7528\u7b49\u8ddd\u6837\u4f8b(<\/span>equidistant samples)<\/span>\u5bf9\u5176\u8fdb\u884c\u91c7\u6837(<\/span>sample)<\/span>?<\/div>\n<\/li>\n
  1654. \n
     <\/div>\n<\/li>\n
  1655. \n
    (<\/span>\u63d0\u793a: np.cumsum<\/span>,<\/span> np.interp<\/span>)<\/span><\/div>\n<\/li>\n
  1656. \n
     <\/div>\n<\/li>\n
  1657. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1658. \n
     <\/div>\n<\/li>\n
  1659. \n
    # phi = np.arange(0, 10*np.pi, 0.1)<\/span><\/div>\n<\/li>\n
  1660. \n
     <\/div>\n<\/li>\n
  1661. \n
    # a = 1<\/span><\/div>\n<\/li>\n
  1662. \n
     <\/div>\n<\/li>\n
  1663. \n
    # x = a*phi*np.cos(phi)<\/span><\/div>\n<\/li>\n
  1664. \n
     <\/div>\n<\/li>\n
  1665. \n
    # y = a*phi*np.sin(phi)<\/span><\/div>\n<\/li>\n
  1666. \n
     <\/div>\n<\/li>\n
  1667. \n
    # dr = (np.diff(x)**2 + np.diff(y)**2)**.5 # segment lengths<\/span><\/div>\n<\/li>\n
  1668. \n
     <\/div>\n<\/li>\n
  1669. \n
    # r = np.zeros_like(x)<\/span><\/div>\n<\/li>\n
  1670. \n
     <\/div>\n<\/li>\n
  1671. \n
    # r[1:] = np.cumsum(dr) # integrate path<\/span><\/div>\n<\/li>\n
  1672. \n
     <\/div>\n<\/li>\n
  1673. \n
    # r_int = np.linspace(0, r.max(), 200) # regular spaced path<\/span><\/div>\n<\/li>\n
  1674. \n
     <\/div>\n<\/li>\n
  1675. \n
    # x_int = np.interp(r_int, r, x) # integrate path<\/span><\/div>\n<\/li>\n
  1676. \n
     <\/div>\n<\/li>\n
  1677. \n
    # y_int = np.interp(r_int, r, y)<\/span><\/div>\n<\/li>\n
  1678. \n
     <\/div>\n<\/li>\n
  1679. \n
    99<\/span>. \u7ed9\u5b9a\u6574\u6570n\u548c2D\u6570\u7ec4X\uff0c\u4eceX\u4e2d\u9009\u62e9\u53ef\u4ee5\u89e3\u91ca\u4e3a\u5177\u6709n\u5ea6\u7684\u591a\u9879\u5206\u5e03\u7684\u7ed8\u5236\u7684\u884c\uff0c\u5373\uff0c\u4ec5\u5305\u542b\u6574\u6570\u5e76\u4e14\u603b\u548c\u4e3an\u7684\u884c\u3002<\/div>\n<\/li>\n
  1680. \n
     <\/div>\n<\/li>\n
  1681. \n
    (<\/span>\u63d0\u793a: np.logical_and<\/span>.reduce<\/span>,<\/span> np.mod<\/span>)<\/span><\/div>\n<\/li>\n
  1682. \n
     <\/div>\n<\/li>\n
  1683. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1684. \n
     <\/div>\n<\/li>\n
  1685. \n
    # X = np.asarray([[1.0, 0.0, 3.0, 8.0],<\/span><\/div>\n<\/li>\n
  1686. \n
     <\/div>\n<\/li>\n
  1687. \n
    # [2.0, 0.0, 1.0, 1.0],<\/span><\/div>\n<\/li>\n
  1688. \n
     <\/div>\n<\/li>\n
  1689. \n
    # [1.5, 2.5, 1.0, 0.0]])<\/span><\/div>\n<\/li>\n
  1690. \n
     <\/div>\n<\/li>\n
  1691. \n
    # n = 4<\/span><\/div>\n<\/li>\n
  1692. \n
     <\/div>\n<\/li>\n
  1693. \n
    # M = np.logical_and.reduce(np.mod(X, 1) == 0, axis=-1)<\/span><\/div>\n<\/li>\n
  1694. \n
     <\/div>\n<\/li>\n
  1695. \n
    # M &= (X.sum(axis=-1) == n)<\/span><\/div>\n<\/li>\n
  1696. \n
     <\/div>\n<\/li>\n
  1697. \n
    # print (X[M])<\/span><\/div>\n<\/li>\n
  1698. \n
     <\/div>\n<\/li>\n
  1699. \n
    100<\/span>. \u8ba1\u7b971D\u9635\u5217X\u7684\u5e73\u5747\u503c\u7684\u81ea\u4e3e95<\/span>\uff05\u7f6e\u4fe1\u533a\u95f4\uff08\u5373\uff0c\u5bf9\u66ff\u6362N\u6b21\u7684\u9635\u5217\u7684\u5143\u7d20\u8fdb\u884c\u91cd\u65b0\u91c7\u6837\uff0c\u8ba1\u7b97\u6bcf\u4e2a\u6837\u672c\u7684\u5e73\u5747\u503c\uff0c\u7136\u540e\u8ba1\u7b97\u5747\u503c\u4e0a\u7684\u767e\u5206\u4f4d\u6570\uff09\u3002<\/div>\n<\/li>\n
  1700. \n
     <\/div>\n<\/li>\n
  1701. \n
    In [<\/span> ]<\/span>:<\/div>\n<\/li>\n
  1702. \n
     <\/div>\n<\/li>\n
  1703. \n
    # X = np.random.randn(100) # random 1D array<\/span><\/div>\n<\/li>\n
  1704. \n
     <\/div>\n<\/li>\n
  1705. \n
    # N = 1000 # number of bootstrap samples<\/span><\/div>\n<\/li>\n
  1706. \n
     <\/div>\n<\/li>\n
  1707. \n
    # idx = np.random.randint(0, X.size, (N, X.size))<\/span><\/div>\n<\/li>\n
  1708. \n
     <\/div>\n<\/li>\n
  1709. \n
    # means = X[idx].mean(axis=1)<\/span><\/div>\n<\/li>\n
  1710. \n
     <\/div>\n<\/li>\n
  1711. \n
    # confint = np.percentile(means, [2.5, 97.5])<\/span><\/div>\n<\/li>\n
  1712. \n
     <\/div>\n<\/li>\n
  1713. \n
    # print (confint)<\/span><\/div>\n<\/li>\n<\/ol>\n<\/div>\n<\/div>\n<\/div>\n
    GeSHi © Codebox Plus Extension<\/div>\n<\/div>\n

    \u539f\u6587\u4f5c\u8005: BG6RSH | \u67e5\u770b\u539f\u5e16<\/a><\/small><\/p>\n","protected":false},"excerpt":{"rendered":"

    Numpy\u662f\u7528Python\u505a\u6570\u636e\u5206\u6790\u6240\u5fc5\u987b\u8981\u638c\u63e1\u7684\u57fa\u7840\u5e93\u4e4b\u4e00\uff0c\u5b83\u53ef\u4ee5\u7528\u6765\u5b58\u50a8\u548c\u5904 … \u7ee7\u7eed\u9605\u8bfb →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[105],"tags":[],"class_list":["post-1464","post","type-post","status-publish","format-standard","hentry","category-105"],"_links":{"self":[{"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=\/wp\/v2\/posts\/1464","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1464"}],"version-history":[{"count":0,"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=\/wp\/v2\/posts\/1464\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1464"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1464"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tansoo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1464"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}