The numpy.nanargmin() function returns indices of the min element of the array in a particular axis ignoring NaNs.
The results cannot be trusted if a slice contains only NaNs and Infs.
Syntax:
numpy.nanargmin(array, axis = None)
Parameters :
array : Input array to work on axis : [int, optional]Along a specified axis like 0 or 1
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 nanargmin()import numpy as geek # Working on 1D arrayarray = [geek.nan, 4, 2, 3, 1]print("INPUT ARRAY 1 : \n", array)array2 = geek.array([[geek.nan, 4], [1, 3]])# returning Indices of the min element# as per the indices ingnoring NaNprint("\nIndices of min in array1 : ", geek.nanargmin(array))# Working on 2D arrayprint("\nINPUT ARRAY 2 : \n", array2)print("\nIndices of min in array2 : ", geek.nanargmin(array2))print("\nIndices at axis 1 of array2 : ", geek.nanargmin(array2, axis = 1)) |
Output :
INPUT ARRAY 1 : [nan, 4, 2, 3, 1] Indices of min in array1 : 4 INPUT ARRAY 2 : [[ nan 4.] [ 1. 3.]] Indices of min in array2 : 2 Indices at axis 1 of array2 : [1 0]
Code 2 : Comparing working of argmin and nanargmin
Python
# Python Program illustrating# working of nanargmin()import numpy as geek # Working on 2D arrayarray = ( [[ 8, 13, 5, 0], [ geek.nan, geek.nan, 5, 3], [10, 7, 15, 15], [3, 11, 4, 12]])print("INPUT ARRAY : \n", array)# returning Indices of the min element# as per the indices ''' [[ 8 13 5 0] [ 0 2 5 3] [10 7 15 15] [ 3 11 4 12]] ^ ^ ^ ^ 0 2 4 0 - element 1 1 3 0 - indices'''print("\nIndices of min using argmin : ", geek.argmin(array, axis = 0))print("\nIndices of min using nanargmin : : ", geek.nanargmin(array, axis = 0)) |
Output :
INPUT ARRAY : [[ 8 13 5 0] [ 0 2 5 3] [10 7 15 15] [ 3 11 4 12]] Indices of min element : [1 1 3 0]
References :
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.nanargmin.html
Note :
These codes won’t run on online IDE’s. So please, run them on your systems to explore the working.
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