code: def ma(self):
          
          a = self.array
          return numpy.ma.MaskedArray(a, mask=numpy.logical_not(numpy.isfinite(a)))
docs: Represent data as a masked array.
  
          The array is returned with column-first indexing, i.e. for a data file with
          columns X Y1 Y2 Y3 ... the array a will be a[0] = X, a[1] = Y1, ... .
  
          inf and nan are filtered via :func:`numpy.isfinite`.