python-generator生成杨辉三角

根据廖雪峰老师的评论区摘录。

1：

 def triangles():
     L = [1]
     while True:
         yield L
         L1 = [0] + L[:]
         L = [L[i]+L1[i] for i in range(len(L))] + [1]

2：

 def triangles():
     L = [1]
     while True:
         yield L
         L.append(0);
         L = [L[i-1] + L[i] for i in range(len(L))]

输出结果：

# 期待输出:
# [1]
# [1, 1]
# [1, 2, 1]
# [1, 3, 3, 1]
# [1, 4, 6, 4, 1]
# [1, 5, 10, 10, 5, 1]
# [1, 6, 15, 20, 15, 6, 1]
# [1, 7, 21, 35, 35, 21, 7, 1]
# [1, 8, 28, 56, 70, 56, 28, 8, 1]
# [1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
n = 0
for t in triangles():
    print(t)
    n = n + 1
    if n == 10:
        break