Numpy: change max in each row to 1, all other numbers to 0

Question

I\'m trying to implement a numpy function that replaces the max in each row of a 2D array with 1, and all other numbers with zero:

>>> a = np.array(         


        

Answer 1

a==np.max(a) will raise an error in the future, so here's a tweaked version that will continue to broadcast correctly.

I know this question is pretty ancient, but I think I have a decent solution that's a bit different from the other solutions.

# get max by row and convert from (n, ) -> (n, 1) which will broadcast
row_maxes = a.max(axis=1).reshape(-1, 1)
np.where(a == row_maxes, 1, 0)
np.where(a == row_maxes).astype(int)

if the update needs to be in place, you can do

a[:] = np.where(a == row_maxes, 1, 0)