努比。Python中的argmax（）-yiteyi-C++库

这个 努比。argmax（） 函数返回数组在特定轴上的最大元素的索引。

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语法：

numpy.argmax(array, axis = None, out = None)

参数：

array : Input array to work on axis  : [int, optional]Along a specified axis like 0 or 1out   : [array optional]Provides a feature to insert output to the out          array and it should be of appropriate shape and dtype

返回：

Array of indices into the array with same shape as array.shape with the dimension along axis removed.

代码1：

python

                         # Python Program illustrating                       
                         # working of argmax()                       
           
                         import                                     numpy as geek                       
           
                         # Working on 2D array                       
                         array                                     =                                     geek.arrange(                                     12                                     ).reshape(                                     3                                     ,                                     4                                     )                       
                         print                                     (                                     "INPUT ARRAY : "                                     , array)                       
           
                         # No axis mentioned, so works on entire array                       
                         print                                     (                                     "Max element : "                                     , geek.argmax(array))                       
           
                         # returning Indices of the max element                       
                         # as per the indices                       
                         print                                     (                                     "Indices of Max element : "                                     , geek.argmax(array, axis                                     =                                     0                                     ))                       
                         print                                     (                                     "Indices of Max element : "                                     , geek.argmax(array, axis                                     =                                     1                                     ))                       

输出：

INPUT ARRAY :  [[ 0  1  2  3] [ 4  5  6  7] [ 8  9 10 11]]Max element :  11Indices of Max element :  [2 2 2 2]Indices of Max element :  [3 3 3]

代码2：

python

                         # Python Program illustrating                       
                         # working of argmax()                       
           
                         import                                     numpy as geek                       
           
                         # Working on 2D array                       
                         array                                     =                                     geek.random.randint(                                     16                                     , size                                     =                                     (                                     4                                     ,                                     4                                     ))                       
                         print                                     (                                     "INPUT ARRAY : "                                     , array)                       
           
                         # No axis mentioned, so works on entire array                       
                         print                                     (                                     "Max element : "                                     , geek.argmax(array))                       
           
                         # returning Indices of the max element                       
                         # as per the indices                       
           
                         '''                       
                                                 [[ 0  3  8 13]                       
                                                 [12 11  2 11]                       
                                                 [ 5 13  8  3]                       
                                                 [12 15  3  4]]                       
                                                 ^  ^  ^  ^                       
                                                 12 15  8  13  - element                       
                                                 1  3   0  0   - indices                       
                         '''                       
                         print                                     (                                     "Indices of Max element : "                                     , geek.argmax(array, axis                                     =                                     0                                     ))                       
           
           
                         '''                       
                                                 ELEMENT   INDEX                       
                                                 ->[[ 0  3  8 13]           13        3                       
                                                 ->[12 11  2 11]           12        0                       
                                                 ->[ 5 13  8  3]           13        1                       
                                                 ->[12 15  3  4]]          15        1                       
                                   
                         '''                       
                         print                                     (                                     "Indices of Max element : "                                     , geek.argmax(array, axis                                     =                                     1                                     ))                       

输出：

INPUT ARRAY :  [[ 0  3  8 13]  [12 11  2 11]  [ 5 13  8  3]  [12 15  3  4]]Max element :  15Indices of Max element :  [1 3 0 0]Indices of Max element :  [3 0 1 1]

代码3：

python

                         # Python Program illustrating                       
                         # working of argmax()                       
           
                         import                                     numpy as geek                       
           
                         # Working on 2D array                       
                         array                                     =                                     geek.arrange(                                     10                                     ).reshape(                                     2                                     ,                                     5                                     )                       
                         print                                     (                                     "array : "                                     , array)                       
           
                         array[                                     0                                     ][                                     1                                     ]                                     =                                     6                       
                         print                                     (                                     "array : "                                     , array)                       
                                   
                         # Returns max element                       
                         print                                     (                                     "array : "                                     , geek.argmax(array))                       
           
                         # First occurrence of an max element is given                       
                         print                                     (                                     "MAX ELEMENT INDICES : "                                     , geek.argmax(array, axis                                     =                                     0                                     ))                       

输出：

array :  [[0 1 2 3 4] [5 6 7 8 9]]array :  [[0 6 2 3 4] [5 6 7 8 9]]array :  9MAX ELEMENT INDICES :  [1 0 1 1 1]

参考资料： https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.argmax.html#numpy.argmax

注：这些代码不会在online-ID上运行。请在您的系统上运行它们以探索工作环境。

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