How to delete an element from a numpy array?

Question

Is there any function to delete an element or elements from a numpy array? I tried the remove() function, but it did not work.

Answer 1

The remove() function is for Python list, and it does not work for numpy array. You need to use the delete() function to remove an element or elements from a numpy array. In this function, you need to provide the list and the indices of the elements that you want to delete as arguments. It returns a new array, i.e., the old array will not change.

Here is an example to show how to delete one element or multiple elements. I am using numpy where() function to find the index of an element and the isin() function to find the indices of multiple elements.

>>> import numpy as np

>>> aa=np.asarray([12,32,43,34,56,89])

>>> aa

array([12, 32, 43, 34, 56, 89])

>>> a1=np.delete(aa, np.where(aa==43))

>>> a1

array([12, 32, 34, 56, 89])

>>> a2=np.delete(aa, np.isin(aa,[12,56]).nonzero()[0])

>>> a2

array([32, 43, 34, 89])