list[i][j] in python code example

Example 1: create a 2d array in python

def build_matrix(rows, cols):
    matrix = []

    for r in range(0, rows):
        matrix.append([0 for c in range(0, cols)])

    return matrix

if __name__ == '__main__':
    build_matrix(6, 10)

Example 2: two dimensional array python

# Creates a list containing 5 lists, each of 8 items, all set to 0
w, h = 8, 5;
Matrix = [[0 for y in range(h)] for x in range(w)] 

Matrix[0][0] = 1
Matrix[0][6] = 3 # error! range... 
Matrix[6][0] = 3 # valid