直接上代码，也是网上找的，自己试了试，很好玩，记录一下：
def triangles():
L = [1]
while True:
yield L
L.append(0)
L = [L[i-1]+L[i] for i in range(len(L))]
定义一个函数，输入打印多少行：
def canshu(k):
n = 0
for t in triangles():
print(t)
n = n+1
if n == k:
break
调用：
canshu(10)
打印的结果：
[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]
该方式用到了列表生成式，理解起来较困难，下面是另一种方式：
def triangles():
ret = [1]
while True:
yield ret
for i in range(1, len(ret)):
ret[i] = pre[i] + pre[i - 1]
ret.append(1)
pre = ret[:]
自己可以试试！
