mat.py

#!/usr/bin/python

mat = [[0,1],[1,0]]
print(mat)

#double each element
mat2 = [[ elem * 2 for elem in row] for row in mat]
print(mat2)


double = lambda elem: elem * 2

mat3 = map(lambda row: map(double, row), mat) 
print(mat3) # python3 prints <map object 0xaddress>


# 2D map function
def map2d(fn, mat):
	return map(lambda row: map(fn, row), mat)

mat4 = map2d(double, mat)
print(mat4) # WTF is this <map object>?


# map2d with explicit cast
def map2d_list(fn, mat):
	return list(map(lambda row: list(map(fn, row)), mat))

mat5 = map2d_list(double,mat)
print(mat5) # works as expected