Alter the masked value symbol - - when printing a masked Numpy array

Question

I am looking for a way to alter the -- masked value symbol when printing a masked Numpy array

Answer 1

Poking around in the np.ma module, and the methods of a masked array I found

np.ma.masked_print_option
"Handle the string used to represent missing data in a masked array."

The default '--':

In [619]: np.ma.masked_print_option.display()
Out[619]: '--'

changed to 'xx'

In [620]: np.ma.masked_print_option.set_display('xx')

In [621]: M
Out[621]: 
masked_array(data = [0 xx 2 xx 4 xx 6 xx 8 xx],
             mask = [False  True False  True False  True False  True False  True],
       fill_value = 999999)