numpy.ma.count_masked¶
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numpy.ma.
count_masked
(arr, axis=None)[source]¶ Count the number of masked elements along the given axis.
Parameters: arr : array_like
An array with (possibly) masked elements.
axis : int, optional
Axis along which to count. If None (default), a flattened version of the array is used.
Returns: count : int, ndarray
The total number of masked elements (axis=None) or the number of masked elements along each slice of the given axis.
See also
MaskedArray.count
- Count non-masked elements.
Examples
>>> import numpy.ma as ma >>> a = np.arange(9).reshape((3,3)) >>> a = ma.array(a) >>> a[1, 0] = ma.masked >>> a[1, 2] = ma.masked >>> a[2, 1] = ma.masked >>> a masked_array(data = [[0 1 2] [-- 4 --] [6 -- 8]], mask = [[False False False] [ True False True] [False True False]], fill_value=999999) >>> ma.count_masked(a) 3
When the axis keyword is used an array is returned.
>>> ma.count_masked(a, axis=0) array([1, 1, 1]) >>> ma.count_masked(a, axis=1) array([0, 2, 1])