Check if column or diagonal in matrix = x (Without Numpy)

Question

I can use this code to check if a row in a matrix = x:

q = [[1,2,1],[1,2,1],[2,1,2]]
answer = [sum(row) for row in q]
for i in range(0, len(q)):
    if answe         


        

Answer 1

How about this? Works for an arbitrary shape of q

def check_col_diag (q, x):
    """
    Returns:
    0 if there was a column,
    1 if there was a row,
    2 if there was a diagonal on 1st direction
    3 if there was a diagonal on 2nd direction
    """

    # Get a mask to store the positions
    # on each row of q where q == x
    mask = q
    for row_ix in range(len(q[0])):
        for elem_ix in range(len(q[1])):
            if q[row_ix][elem_ix] == x:
                mask[row_ix][elem_ix] = 1
            else:
                mask[row_ix][elem_ix] = 0

    # Check rows
    c = [1]*len(q[0])
    for row in mask:
        # element-wise list multiplication
        c = [a*b for a,b in zip(c,row)]
    # Return 0 if there was a column
    if any(c):
        return 0

    # Check columns 
    c = [1]*len(q[1])
    # Iterate through rows of transposed list
    _q = list(map(list, zip(*mask)))
    for row in _q:
        c = [a*b for a,b in zip(c,row)]
    # Return 1 if there was a row
    if any(c):
        return 1

    # Check diagonal 1
    c = 1
    for row_ix in range(len(q[0])):
        c *= mask[row_ix][row_ix]
    # Return 2 if there was a 1st diagonal
    if c == 1:
        return 2

    # Check diagonal 2
    c = 1
    for row_ix in range(len(_q[0])):
        c *= mask[row_ix][row_ix]
    # Return 3 if there was a 2nd diagonal
    if c == 1:
        return 3


q = [[1,2,1],[1,2,1],[2,1,2]]
v = check_col_diag (q, 1)