dask.array.flatnonzero — Dask documentation (original) (raw)

dask.array.flatnonzero¶

dask.array.flatnonzero(a)[source]¶

Return indices that are non-zero in the flattened version of a.

This docstring was copied from numpy.flatnonzero.

Some inconsistencies with the Dask version may exist.

This is equivalent to np.nonzero(np.ravel(a))[0].

Parameters

aarray_like

Input data.

Returns

resndarray

Output array, containing the indices of the elements of a.ravel()that are non-zero.

See also

nonzero

Return the indices of the non-zero elements of the input array.

ravel

Return a 1-D array containing the elements of the input array.

Examples

import numpy as np
x = np.arange(-2, 3)
x
array([-2, -1, 0, 1, 2]) np.flatnonzero(x)
array([0, 1, 3, 4])

Use the indices of the non-zero elements as an index array to extract these elements:

x.ravel()[np.flatnonzero(x)]
array([-2, -1, 1, 2])