Empty masked array with all elements masked.
Return an empty masked array of the given shape and dtype, where all the data are masked.
| Parameters : | shape : tuple 
 dtype : dtype, optional 
  | 
|---|---|
| Returns : | a : MaskedArray 
  | 
See also
Examples
>>> import numpy.ma as ma
>>> ma.masked_all((3, 3))
masked_array(data =
 [[-- -- --]
 [-- -- --]
 [-- -- --]],
      mask =
 [[ True  True  True]
 [ True  True  True]
 [ True  True  True]],
      fill_value=1e+20)
The dtype parameter defines the underlying data type.
>>> a = ma.masked_all((3, 3))
>>> a.dtype
dtype('float64')
>>> a = ma.masked_all((3, 3), dtype=np.int32)
>>> a.dtype
dtype('int32')