Question

以下是绘制数字树的程序，但我无法避免使用“if”语句

# -*- coding: cp1252 -*-
import sys
def xmasTree():
    centre=35
    inicial=1
    level=input("¿Triangle height? \n\t")
    for height in range (inicial,level+1): 
        for index in range(1,centre-height):
            sys.stdout.write(' ') 
        sys.stdout.write(str(inicial)) 
        for index in range(inicial+1,height): 
            sys.stdout.write(str(index))
        for index in range(height,inicial,-1):
            sys.stdout.write(str(index))
        if height>1:
            sys.stdout.write('1')
        sys.stdout.write('\n')
xmasTree()

*编辑：最后我找到了我想要的东西。显然我没有正确解释自己。无论如何，谢谢大家！

这是正确的代码：

# -*- coding: cp1252 -*-
import sys
def xmasTree():
    centre=35
    sep=1
    initial=1
    level=input("¿Triangle height? \n\t")
    for height in range (1,level+1): 
        for index in range(1,centre-height):
            sys.stdout.write(' ') 
        sys.stdout.write(str(sep))
        for index in range(initial+1,height+1):
          sys.stdout.write(str(index))
        for index in range(height+1,initial+1,-1):
             sys.stdout.write(str(index-2))
        sys.stdout.write('\n')

正确的输出：

                         1
                        121
                       12321
                      1234321
                     123454321
                    12345654321
                   1234567654321
                  123456787654321
                 12345678987654321

Answer 1

递归函数：

def xmasTree(n,v=0):
    if n > 0:
        xmasTree(n-2, v+1)
        print " " * v + "".join(str(x%10) for x in range(n))
xmasTree(31)

Answer 2

height = 5
inicial = 2    
for l in range(initial, height):
     line = ''.join( 
                    str( max(l-i, i-l)+1 ) for i in range(2*l+1)
               )
     # {:^35} centers a string within 35 characters, look up python string formatting
     print( '{:^35}'.format(line) )

<强>输出

避免程序中的“if”语句绘制数字树

2 个答案: