Python（四）生成器 和 杨辉三角

# -*- coding: utf-8 -*-

def triangles():

# 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
results = []
for t in triangles():
    print(t)
    results.append(t)
    n = n + 1
    if n == 10:
        break
if results == [
    [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]
]:
    print(‘测试通过!‘)
else:
    print(‘测试失败!‘)

然后在参考了一些博客之后，找到了一个相对我能理解的，并之后自己写出来的一个方法：

def triangles():
    templist=[]
    mylist=[1]
    while True:
        yield mylist

        mylist.append(0)
        for n in range(len(mylist)):
            templist.append(mylist[n]+mylist[n-1])
        mylist=templist
        templist=[];

自己去用笔算一下，

然后注意下 range函数的作用：

range[5]=[0,1,2,3,4]

然后就知道该怎么样了