Python generator ------ 打印杨辉三角

用 for 循环来遍历列表中所有值，一般做法是首先用range(i,j)生成这个列表

g = range(1, 20)
for i in g:
	print(i)

我们可以创建一个generator类型的变量g,

g = (x for x in range(1, 20))
for i in g:
	print(i)

实现同样的效果.

我们也可以自定义一个返回值类型为generator的函数，比如打印杨辉三角：

def triangles(m):
	if m <= 0:
		print("invalid input.")
		exit()
	i = 0
	bt = [1]
	b = [1]
	if m == 1:
		yield b
		exit()
	while i < m:
		yield b
		for j in range(1,len(b)):
			b[j] = bt[j-1]+bt[j]
		b.append(1)
		bt = [x for x in b]
		i = i + 1
#-------------------------------------------------
for i in triangles(20):
	print(i)
"""
输出结果：
[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]
[1, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1]
[1, 11, 55, 165, 330, 462, 462, 330, 165, 55, 11, 1]
[1, 12, 66, 220, 495, 792, 924, 792, 495, 220, 66, 12, 1]
[1, 13, 78, 286, 715, 1287, 1716, 1716, 1287, 715, 286, 78, 13, 1]
[1, 14, 91, 364, 1001, 2002, 3003, 3432, 3003, 2002, 1001, 364, 91, 14, 1]
[1, 15, 105, 455, 1365, 3003, 5005, 6435, 6435, 5005, 3003, 1365, 455, 105, 15, 1]
[1, 16, 120, 560, 1820, 4368, 8008, 11440, 12870, 11440, 8008, 4368, 1820, 560, 120, 16, 1]
[1, 17, 136, 680, 2380, 6188, 12376, 19448, 24310, 24310, 19448, 12376, 6188, 2380, 680, 136, 17, 1]
[1, 18, 153, 816, 3060, 8568, 18564, 31824, 43758, 48620, 43758, 31824, 18564, 8568, 3060, 816, 153, 18, 1]
[1, 19, 171, 969, 3876, 11628, 27132, 50388, 75582, 92378, 92378, 75582, 50388, 27132, 11628, 3876, 969, 171, 19, 1]
[Finished in 0.2s]
"""

generator每一次执行到yield就返回。

最后

以上就是孝顺乌冬面为你收集整理的Python generator ------ 打印杨辉三角的全部内容，希望文章能够帮你解决Python generator ------ 打印杨辉三角所遇到的程序开发问题。

如果觉得靠谱客网站的内容还不错，欢迎将靠谱客网站推荐给程序员好友。