def printLowerTriangular(matrix):
rows = len(m);
cols = len(m[0]);
if (rows != cols):
print("Not a square matrix");
else:
for i in range(0, rows):
for j in range(0, cols):
if (i < j):
print("0", end = " ");
else:
print(m[i][j], end = " ");
print(" ");
m = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
];
printLowerTriangular(m)
'''
run:
1 0 0
4 5 0
7 8 9
'''