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# numpy.ma.MaskedArray.tolist

method

ma.MaskedArray.tolist(fill_value=None)

  Return the data portion of the masked array as a hierarchical Python list.

  Data items are converted to the nearest compatible Python type. Masked values are converted to `fill_value`. If `fill_value` is None, the corresponding entries in the output list will be `None`.

  Parameters:
    fill_value scalar, optional

      The value to use for invalid entries. Default is None.

  Returns:
    result list

      The Python list representation of the masked array.

  Examples

      >>> import numpy as np
      >>> x = np.ma.array([[1,2,3], [4,5,6], [7,8,9]], mask=[0] + [1,0]*4)
      >>> x.tolist()
      [[1, None, 3], [None, 5, None], [7, None, 9]]
      >>> x.tolist(-999)
      [[1, -999, 3], [-999, 5, -999], [7, -999, 9]]