numpy.argmax() in Python (original) (raw)

Last Updated : 08 Mar, 2024

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

import numpy as geek

array = geek.arange( 12 ).reshape( 3 , 4 )

print ( "INPUT ARRAY : \n" , array)

print ( "\nMax element : " , geek.argmax(array))

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

import numpy as geek

array = geek.random.randint( 16 , size = ( 4 , 4 ))

print ( "INPUT ARRAY : \n" , array)

print ( "\nMax element : " , geek.argmax(array))

print ( "\nIndices of Max element : " , geek.argmax(array, axis = 0 ))

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

import numpy as geek

array = geek.arange( 10 ).reshape( 2 , 5 )

print ( "array : \n" , array)

array[ 0 ][ 1 ] = 6

print ( "\narray : \n" , array)

print ( "\narray : " , geek.argmax(array))

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.