PYTHON

2d list in python

ar = [[0 for j in range(m)] for i in range(n)]

2d list in python

def list_2D(r, c):
    l = []
    for i in range(r):
        x = [0] * c
        l.append(x)
    return l

how to create one list from 2d list python

>>> l = [[1, 2, 3], [4, 5, 6], [7], [8, 9]]
>>> sum(l, [])
[1, 2, 3, 4, 5, 6, 7, 8, 9]

python declare 2d list

length, breadth = x, y
matrix = [[-1 for j in range(breadth)] for i in range(length)]
# every element is -1