python打印杨辉三角

python打印杨辉三角，默认在每行的首位各加一个0，则使算法更加简单def triangles(m):
    L = [1]
    n = 0
    while n < m:
        # yield L
        print(L)
        L = [0] L [0]
        L = [L[i] L[i 1] for i in range(len(L) - 1)]
        n = 1

triangles(10)