numpy.delete — NumPy v2.2 Manual (original) (raw)

numpy.delete(arr, obj, axis=None)[source]#

Return a new array with sub-arrays along an axis deleted. For a one dimensional array, this returns those entries not returned by_arr[obj]_.

Parameters:

arrarray_like

Input array.

objslice, int, array-like of ints or bools

Indicate indices of sub-arrays to remove along the specified axis.

Changed in version 1.19.0: Boolean indices are now treated as a mask of elements to remove, rather than being cast to the integers 0 and 1.

axisint, optional

The axis along which to delete the subarray defined by obj. If axis is None, obj is applied to the flattened array.

Returns:

outndarray

A copy of arr with the elements specified by obj removed. Note that delete does not occur in-place. If axis is None, out is a flattened array.

See also

insert

Insert elements into an array.

append

Append elements at the end of an array.

Notes

Often it is preferable to use a boolean mask. For example:

arr = np.arange(12) + 1 mask = np.ones(len(arr), dtype=bool) mask[[0,2,4]] = False result = arr[mask,...]

Is equivalent to np.delete(arr, [0,2,4], axis=0), but allows further use of mask.

Examples

import numpy as np arr = np.array([[1,2,3,4], [5,6,7,8], [9,10,11,12]]) arr array([[ 1, 2, 3, 4], [ 5, 6, 7, 8], [ 9, 10, 11, 12]]) np.delete(arr, 1, 0) array([[ 1, 2, 3, 4], [ 9, 10, 11, 12]])

np.delete(arr, np.s_[::2], 1) array([[ 2, 4], [ 6, 8], [10, 12]]) np.delete(arr, [1,3,5], None) array([ 1, 3, 5, 7, 8, 9, 10, 11, 12])