bundles / numpy 2.5.0.dev0+git20251130.2de293a / numpy / _core / _multiarray_umath / putmask

built-in

`numpy._core._multiarray_umath:putmask`

Signature

built-in putmask ( a , / , mask , values )

Summary

Changes elements of an array based on conditional and input values.

Extended Summary

Sets a.flat[n] = values[n] for each n where mask.flat[n]==True.

If values is not the same size as a and mask then it will repeat. This gives behavior different from a[mask] = values.

Parameters

a : ndarray: Target array.
mask : array_like: Boolean mask array. It has to be the same shape as a.
values : array_like: Values to put into a where mask is True. If values is smaller than a it will be repeated.

Examples

import numpy as np
x = np.arange(6).reshape(2, 3)
np.putmask(x, x>2, x**2)
x

If `values` is smaller than `a` it is repeated:

x = np.arange(5)
np.putmask(x, x>1, [-33, -44])
x

See also

copyto
place
put
take

Aliases

numpy._core._multiarray_umath.putmask