Python lambda with double loops -

is possible rewrite following code lambda expression?

for h in range(height):     w in range(width):         if maskimg[h][w] > 0:             maskimg[h][w] = srcimg[h][w] 

this not equivalent expression since not in-place, achieve same end matrix using like:

lambda_function = lambda height, width, src, mask: [[src[h][w] if mask[h][w] > 0 else mask[h][w] w in range(width)] h in range(height)] 

but not recommend using it, ever. if you're after speed should use numpy these kinds of things. assuming src , mask stored in python-lists, same result much, faster doing:

import numpy np src_np = np.array(src) mask_np = np.array(mask) mask_np[mask_np > 0] = src_np[mask_np > 0] 

which on computer ~50 times faster solution.