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# numpy.ma.putmask

ma.putmask(a, mask, values)

  Changes elements of an array based on conditional and input values.

  This is the masked array version of `numpy.putmask`, for details see `numpy.putmask`.

  See also

  `numpy.putmask`

  Notes

  Using a masked array as values will not transform a `ndarray` into a `MaskedArray`.

  Examples

      >>> import numpy as np
      >>> arr = [[1, 2], [3, 4]]
      >>> mask = [[1, 0], [0, 0]]
      >>> x = np.ma.array(arr, mask=mask)
      >>> np.ma.putmask(x, x < 4, 10*x)
      >>> x
      masked_array(
        data=[[--, 20],
              [30, 4]],
        mask=[[ True, False],
              [False, False]],
        fill_value=999999)
      >>> x.data
      array([[10, 20],
             [30,  4]])