numpy.ma.MaskedArray.tolist() function – Python

numpy.ma.MaskedArray.tolist() function return the data portion of the masked array as a hierarchical Python list.

Syntax : numpy.ma.MaskedArray.tolist(fill_value = None)

Parameters :
axis : [scalar, optional] The value to use for invalid entries. Default is None.

Return : [list] The Python list representation of the masked array.

Code #1 :

# Python program explaining
# numpy.ma.MaskedArray.tolist() function

# importing numpy as geek
# and numpy.ma module as ma
import numpy as geek
import numpy.ma as ma

arr = geek.ma.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
                               mask =[0] + [1, 0] * 4)

gfg = arr.tolist()

print (gfg)

Output :

[[1, None, 3], [None, 5, None], [7, None, 9]]

Code #2 :

# Python program explaining
# numpy.ma.MaskedArray.tolist() function

# importing numpy as geek
# and numpy.ma module as ma
import numpy as geek
import numpy.ma as ma

arr = geek.ma.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
                              mask =[0] + [1, 0] * 4)

gfg = arr.tolist(-999)

print (gfg)

Output :

[[1, -999, 3], [-999, 5, -999], [7, -999, 9]]