`numpy.ma.core:is_mask`

source: /numpy/ma/core.py :1517

Signature

def is_mask ( m )

Summary

Return True if m is a valid, standard mask.

Extended Summary

This function does not check the contents of the input, only that the type is MaskType. In particular, this function returns False if the mask has a flexible dtype.

Parameters

m : array_like: Array to test.

Returns

result : bool: True if m.dtype.type is MaskType, False otherwise.

Examples

import numpy as np
import numpy.ma as ma
m = ma.masked_equal([0, 1, 0, 2, 3], 0)
m
ma.is_mask(m)
ma.is_mask(m.mask)

Input must be an ndarray (or have similar attributes) for it to be considered a valid mask.

m = [False, True, False]
ma.is_mask(m)
m = np.array([False, True, False])
m
ma.is_mask(m)

Arrays with complex dtypes don't return True.

dtype = np.dtype({'names':['monty', 'pithon'],
                  'formats':[bool, bool]})
dtype
m = np.array([(True, False), (False, True), (True, False)],
             dtype=dtype)
m
ma.is_mask(m)

Aliases

numpy.ma.is_mask