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 array array = geek.arange(12).reshape(3, 4) print("INPUT ARRAY : \n", array) # No axis mentioned, so works on entire array print("\nMax element : ", geek.argmax(array)) # returning Indices of the max element # as per the indices print("\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 array array = geek.random.randint(16, size=(4, 4)) print("INPUT ARRAY : \n", array) # No axis mentioned, so works on entire array print("\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 array array = geek.arange(10).reshape(2, 5) print("array : \n", array) array[0][1] = 6 print("\narray : \n", array) # Returns max element print("\narray : ", geek.argmax(array)) # First occurrence of an max element is given print("\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]
Note :
These codes won’t run on online IDE’s. Please run them on your systems to explore the working.
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