`numpy:unique_inverse`

Signature

def unique_inverse ( x )

Find the unique elements of x and indices to reconstruct x.

This function is an Array API compatible alternative to

np.unique(x, return_inverse=True, equal_nan=False, sorted=False)

but returns a namedtuple for easier access to each output.

x : array_like: Input array. It will be flattened if it is not already 1-D.

out : namedtuple

The result containing:

values - The unique elements of an input array.
inverse_indices - The indices from the set of unique elements that reconstruct x.

import numpy as np
x = [1, 1, 2]
uniq = np.unique_inverse(x)
uniq.values
uniq.inverse_indices

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