Python使用函数实现杨辉三角

 1 # -*-coding:utf-8 -*-
 2 '''
 3     chapter4_do.py
 4     函数yanghui(n)用于输出n阶杨辉三角
 5 '''
 6 def yanghui(n):
 7     if not str(n).isdecimal() or n<2 or n>25:
 8         print("杨辉三角函数yanghui(n)，参数n必须是不小于2且不大于25的正整数")
 9         return False
10     x=[]
11     for i in range(1,n+1):
12         x.append([1]*i)
13     for i in range(2,n):
14         for j in range(1,i):
15             x[i][j]=x[i-1][j-1]+x[i-1][j]
16 
17     for i in range(n):
18         if n<=10:print(' '*(40-4*i),end='')
19         for j in range(i+1):
20             print('%-8d'%x[i][j],end='')
21         print()
22 
23 
24 if __name__=='__main__':
25     print("模块独立自运行测试输出：")
26     print("一、10阶杨辉三角如下：")
27     yanghui(10)