# numpy.ma.count_masked

ma.count_masked(arr, axis=None)

  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])