This function compares 2 matrices element by element, compares according to the principle that the corresponding elements should have the same parity

def equals(matr1, matr2):
    if len(matr1) != len(matr2):
        return False
    for index1 in range(len(matr1)):
        if len(matr1[index1]) != len(matr2[index1]):
            return False
        for index2 in range(len(matr1[index1])):
            if matr1[index1][index2] % 2 != matr2[index1][index2] % 2:
                return False
    return True

matrix [[1, 2], [3, 4]] # - satisfies the condition
matrix [[4, 6], [4, 5]] # - does not satisfy the condition

how to write this function in one line?

CodePudding user response：

One arguably dirty way to go would be to "map" the matrices to their remainders mod 2 using list comprehensions, then comparing the matrices:

equals = lambda mat1, mat2: [[e1 % 2 for e1 in l1] for l1 in mat1] == [[e2 % 2 for e2 in l2] for l2 in mat2]

you could deduplicate this using a function, cleaning it up a bit:

def matrix_mod(mat, mod):
    return [[e1 % mod for e1 in l1] for l1 in mat]
def equals(mat1, mat2):
    return matrix_mod(mat1, 2) == matrix_mod(mat2, 2)