def triangles():
    list=[1]
    while True:
        yield  list        #generator函数与普通函数的差别：在执行过程中，遇到yield就中断，下次又继续执行
        list = [list[i - 1] + list[i] for i in range(len(list))]    #核心代吗:
        list.insert(0,1) #在开头添加1
        list.append(1) #在后面添加1
if __name__=='__main__':
    n=0
    for t in triangles():
        print(t)      #打印
        n=n+1
        if n==10: #执行10次
            break
```
结果
```
[1]
[1, 2, 1]
[1, 2, 3, 3, 1]
[1, 2, 3, 5, 6, 4, 1]
[1, 2, 3, 5, 8, 11, 10, 5, 1]
[1, 2, 3, 5, 8, 13, 19, 21, 15, 6, 1]
[1, 2, 3, 5, 8, 13, 21, 32, 40, 36, 21, 7, 1]
[1, 2, 3, 5, 8, 13, 21, 34, 53, 72, 76, 57, 28, 8, 1]
[1, 2, 3, 5, 8, 13, 21, 34, 55, 87, 125, 148, 133, 85, 36, 9, 1]
[1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 142, 212, 273, 281, 218, 121, 45, 10, 1]



```