Question

我有一个长度为500的numpy数组，并尝试获取其最大元素的位置。

> type(arr)
<type 'numpy.ndarray'>
> numpy.max(arr)
0.99841506 # the largest value is here the last one, so its position must be 499, but
> numpy.argmax(arr)
249 # argmax returns 249, which is 0.9814647

这个阵列出了什么问题？在其他情况下，argmax工作正常。这是“异常”数组本身：

[ 0.88909795  0.88978061  0.89034673  0.89087944  0.89145257  0.89210397
  0.89276644  0.89334441  0.89382041  0.89412578  0.89432752  0.8944299
  0.89463225  0.89497062  0.89532122  0.89564772  0.8958474   0.89592464
  0.89630575  0.89698798  0.89769293  0.89848076  0.89930387  0.90013392
  0.90104787  0.90194464  0.90295569  0.9039833   0.9050346   0.90606623
  0.90710517  0.90819266  0.90923895  0.91037811  0.91156073  0.91300442
  0.91446512  0.91584151  0.91715882  0.91845024  0.91955421  0.92089298
  0.92244761  0.92398027  0.92523805  0.92643114  0.92755521  0.92864628
  0.92981656  0.93095717  0.93208001  0.93326082  0.93442172  0.93567889
  0.93666403  0.93801784  0.93904143  0.94014266  0.94127314  0.94247457
  0.94350104  0.94388245  0.9446991   0.94563049  0.94652052  0.94740291
  0.94813891  0.94865294  0.94928902  0.94985706  0.95011467  0.95032619
  0.95047542  0.95055906  0.95068319  0.95087543  0.95134286  0.95219489
  0.95271328  0.95308582  0.95367633  0.95438522  0.95537771  0.95626897
  0.95709159  0.95805329  0.95904842  0.96008088  0.96115256  0.96221983
  0.96315547  0.9641299   0.96526232  0.96634076  0.9673133   0.96829591
  0.9692317   0.97008387  0.97076741  0.97145813  0.97215305  0.97273013
  0.97324447  0.97384943  0.97444085  0.97502589  0.97565676  0.9762706
  0.97698153  0.9779038   0.97879313  0.97943701  0.98006739  0.98063262
  0.98096896  0.98130123  0.98159047  0.98172486  0.98169341  0.98158367
  0.98150869  0.9815271   0.98153536  0.98164806  0.98173003  0.98171431
  0.98173717  0.98167403  0.98145793  0.98120804  0.98106709  0.98101609
  0.98112061  0.98114241  0.98098263  0.98089001  0.98085913  0.98073206
  0.98045551  0.98013516  0.9799087   0.97975682  0.97967519  0.97963055
  0.97955903  0.97957455  0.97960247  0.97958315  0.97948352  0.9793838
  0.97931257  0.97913527  0.97756488  0.97743783  0.97723032  0.9771425
  0.97692371  0.97670625  0.97671619  0.9772266   0.97849404  0.97935737
  0.98037385  0.98136674  0.98229204  0.98313426  0.98371021  0.98423502
  0.98475514  0.98519817  0.9853992   0.98522209  0.98544847  0.98585939
  0.9857425   0.9857368   0.98581936  0.98587366  0.98570029  0.98555498
  0.98545724  0.98516041  0.98520702  0.98522651  0.98507088  0.98477696
  0.98442745  0.98415864  0.98401446  0.98404856  0.98404806  0.98411621
  0.98416166  0.98438146  0.98455107  0.98476666  0.98488303  0.98484396
  0.98465454  0.98457754  0.9845227   0.98420963  0.98379581  0.98339187
  0.98296063  0.98215673  0.9818166   0.98136827  0.98092174  0.98064912
  0.98051665  0.98154758  0.98175672  0.98187866  0.98201024  0.98213502
  0.98217471  0.98243727  0.98261784  0.98269089  0.98292136  0.98307152
  0.98319756  0.98345249  0.98336651  0.98425455  0.98513982  0.98601273
  0.98669306  0.98816828  0.98959878  0.99017499  0.99073479  0.99148809
  0.99195023  0.99247333  0.99292418  0.99330445  0.99376024  0.99435036
  0.99501503  0.99565791  0.9943401   0.99495361  0.99539686  0.99585094
  0.99646274  0.99703564  0.99765937  0.99841506]

你可以解释一下吗？我不需要这个数组，但我想确保numpy.argmax的正确性。

PS。

Python 2.7.6（默认，2014年2月23日，01：28：31）[bCC 4.7.3] on linux2

numpy：1.8.0-r1

Answer 1

您的数组有250个元素。它们已编入[0]到[249]的索引。最后一个元素位于[249]，正确找到了它。

行为不正确或numpy.argmax函数（关闭，我在这里失败）

1 个答案: