numpy.argmax() in Python - GeeksforGeeks

28 Mar, 2022
The numpy.argmax() function returns indices of the max element of the array in a particular axis. 
Syntax : 
numpy.argmax(array, axis = None, out = None)
Parameters : 
array : Input array to work on 
axis  : [int, optional]Along a specified axis like 0 or 1
out   : [array optional]Provides a feature to insert output to the out
          array and it should be of appropriate shape and dtype
Return :  
Array of indices into the array with same shape as array.shape
 with the dimension along axis removed.
Code 1 :  
Python
# Python Program illustrating# working of argmax() import numpy as geek # Working on 2D arrayarray = geek.arrange(12).reshape(3, 4)print("INPUT ARRAY : \n", array) # No axis mentioned, so works on entire arrayprint("\nMax element : ", geek.argmax(array)) # returning Indices of the max element# as per the indicesprint("\nIndices of Max element : ", geek.argmax(array, axis=0))print("\nIndices of Max element : ", geek.argmax(array, axis=1))
Output : 
INPUT ARRAY : 
 [[ 0  1  2  3]
 [ 4  5  6  7]
 [ 8  9 10 11]]

Max element :  11

Indices of Max element :  [2 2 2 2]

Indices of Max element :  [3 3 3]
Code 2 :  
Python
# Python Program illustrating# working of argmax() import numpy as geek # Working on 2D arrayarray =  geek.random.randint(16, size=(4, 4))print("INPUT ARRAY : \n", array) # No axis mentioned, so works on entire arrayprint("\nMax 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("\nIndices 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("\nIndices of Max element : ", geek.argmax(array, axis = 1))
Output : 
INPUT ARRAY : 
 [[ 0  3  8 13]
  [12 11  2 11]
  [ 5 13  8  3]
  [12 15  3  4]]

Max element :  15

Indices of Max element :  [1 3 0 0]

Indices of Max element :  [3 0 1 1]
Code 3 : 
Python
# Python Program illustrating# working of argmax() import numpy as geek # Working on 2D arrayarray =  geek.arrange(10).reshape(2, 5)print("array : \n", array) array[0][1] = 6print("\narray : \n", array)      # Returns max elementprint("\narray : ", geek.argmax(array)) # First occurrence of an max element is givenprint("\nMAX ELEMENT INDICES : ", geek.argmax(array, axis = 0))
Output : 
array : 
 [[0 1 2 3 4]
 [5 6 7 8 9]]

array : 
 [[0 6 2 3 4]
 [5 6 7 8 9]]

array :  9

MAX ELEMENT INDICES :  [1 0 1 1 1]
References : https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.argmax.html#numpy.argmax
Note : These codes won’t run on online IDE’s. Please run them on your systems to explore the working.
This article is contributed by Mohit Gupta_OMG . If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. 
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