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

Last Updated : 09 Aug, 2022

The numpy.delete() function returns a new array with the deletion of sub-arrays along with the mentioned axis.

Syntax:

numpy.delete(array, object, axis = None)

Parameters :

array : [array_like]Input array. object : [int, array of ints]Sub-array to delete axis : Axis along which we want to delete sub-arrays. By default, it object is applied to
flattened array

Return :

An array with sub-array being deleted as per the mentioned object along a given axis.

Code 1 : Deletion from 1D array

Python

Output :

arr : [0 1 2 3 4] Shape : (5,)

deleting arr 2 times : [0 1 3 4] Shape : (4,)

deleting arr 3 times : [0 3 4] Shape : (4,)

Code 2 :

Python

import numpy as geek

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

print ( "arr : \n" , arr)

print ( "Shape : " , arr.shape)

a = geek.delete(arr, 1 , 0 )

print ( "\ndeleteing arr 2 times : \n" , a)

print ( "Shape : " , a.shape)

a = geek.delete(arr, 1 , 1 )

print ( "\ndeleteing arr 2 times : \n" , a)

print ( "Shape : " , a.shape)

Output :

arr : [[ 0 1 2 3] [ 4 5 6 7] [ 8 9 10 11]] Shape : (3, 4)

deleting arr 2 times : [[ 0 1 2 3] [ 8 9 10 11]] Shape : (2, 4)

deleting arr 2 times : [[ 0 2 3] [ 4 6 7] [ 8 10 11]] Shape : (3, 3)

deleting arr 3 times : [ 0 3 4 5 6 7 8 9 10 11] Shape : (3, 3)

Code 3: Deletion performed using Boolean Mask

Python

import numpy as geek

arr = geek.arange( 5 )

print ( "Original array : " , arr)

mask = geek.ones( len (arr), dtype = bool )

mask[[ 0 , 2 ]] = False

print ( "\nMask set as : " , mask)

result = arr[mask,...]

print ( "\nDeletion Using a Boolean Mask : " , result)

Output :

Original array : [0 1 2 3 4]

Mask set as : [False True False True True]

Deletion Using a Boolean Mask : [1 3 4]

References :
https://docs.scipy.org/doc/numpy/reference/generated/numpy.delete.html
Note :
These codes won’t run on online IDE’s. Please run them on your systems to explore the working
.