Python implements a method to output the specified input string in reverse order-Python Tutorial-php.cn

Python implements a method to output the specified input string in reverse order

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Release： 2018-04-26 16:31:05

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This article mainly introduces the 6 methods of python to realize the reverse output of the specified input string, which has certain reference value. Interested friends can refer to it

For a given String, output in reverse order. This task is a very simple operation for Python. After all, the powerful list and string processing functions are enough to cope with these problems. Today I summarized the reverse order output of strings in Python. Several commonly used methods, a total of six methods have been summarized. I personally think it is relatively comprehensive. If you have other methods, please feel free to add them.

Method 1:Use the string slicing function directly Reverse the string

Method 2:Convert the string to a list using the reverse function

Method 3:Create a new list from back to front Add elements

Method 4: Use the ready-made method of collections module extendleft

Method 5: Recursive implementation

Method 6: Use the basic Swap operation to exchange symmetrically positioned characters based on the middle

The following is the specific implementation:

#!usr/bin/env python 
#encoding:utf-8 
 
&#39;&#39;&#39;&#39;&#39;&#39;&#39; 
__Author__:沂水寒城 
功能：输入一个字符串，倒叙输出 
&#39;&#39;&#39; 
 
import collections 
 
 
 
def func1(one_str): 
 &#39;&#39;&#39;&#39;&#39; 
 直接使用字符串切片功能逆转字符串 
 &#39;&#39;&#39; 
 return one_str[::-1] 
 
 
def func2(one_str): 
 &#39;&#39;&#39;&#39;&#39; 
 将字符串转换为列表使用reverse函数 
 &#39;&#39;&#39; 
 one_str_list = list(one_str) 
 one_str_list.reverse() 
 return &#39;&#39;.join(one_str_list) 
 
 
def func3(one_str): 
 &#39;&#39;&#39;&#39;&#39; 
 新建一个列表，从后往前添加元素 
 &#39;&#39;&#39; 
 one_list=[] 
 for i in range(len(one_str)-1,-1,-1): 
  one_list.append(one_str[i]) 
 return &#39;&#39;.join(one_list) 
 
 
def func4(one_str): 
 &#39;&#39;&#39;&#39;&#39; 
 借助于collections模块现成的方法extendleft 
 &#39;&#39;&#39; 
 deque1=collections.deque(one_str) 
 deque2=collections.deque() 
 for one_char in deque1: 
  deque2.extendleft(one_char) 
 return &#39;&#39;.join(deque2) 
 
 
def func5(one_str): 
 &#39;&#39;&#39;&#39;&#39; 
 递归实现 
 &#39;&#39;&#39; 
 if len(one_str)<=1: 
  return one_str 
 return one_str[-1]+func5(one_str[:-1]) 
 
 
def func6(one_str): 
 &#39;&#39;&#39;&#39;&#39; 
 借助基本的Swap操作，以中间为基准交换对称位置的字符 
 &#39;&#39;&#39; 
 one_str_list=list(one_str) 
 if len(one_str_list)==0 or len(one_str_list)==1: 
  return one_str_list 
 i=0 
 length=len(one_str_list) 
 while i < length/2: 
  one_str_list[i], one_str_list[length-i-1]=one_str_list[length-i-1], one_str_list[i] 
  i+=1 
 return &#39;&#39;.join(one_str_list) 
 
 
def main_func(str_list): 
 &#39;&#39;&#39;&#39;&#39; 
 主调用函数 
 &#39;&#39;&#39; 
 for one_str in str_list: 
  one_list=[] 
  one=[] 
  one_list.append(func1(one_str)) 
  one_list.append(func2(one_str)) 
  one_list.append(func3(one_str)) 
  one_list.append(func4(one_str)) 
  one_list.append(func5(one_str)) 
  one_list.append(func6(one_str)) 
  print &#39;字符串{0}逆序为：&#39;.format(one_str) 
  print one_list 
 
 
if __name__ == &#39;__main__&#39;: 
 str_list=[&#39;123456&#39;,&#39;abcdefg&#39;,&#39;zyxvuw&#39;,&#39;Together_CZ&#39;] 
 main_func(str_list)

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The results are as follows:

字符串123456逆序为： 
[&#39;654321&#39;, &#39;654321&#39;, &#39;654321&#39;, &#39;654321&#39;, &#39;654321&#39;, &#39;654321&#39;] 
字符串abcdefg逆序为： 
[&#39;gfedcba&#39;, &#39;gfedcba&#39;, &#39;gfedcba&#39;, &#39;gfedcba&#39;, &#39;gfedcba&#39;, &#39;gfedcba&#39;] 
字符串zyxvuw逆序为： 
[&#39;wuvxyz&#39;, &#39;wuvxyz&#39;, &#39;wuvxyz&#39;, &#39;wuvxyz&#39;, &#39;wuvxyz&#39;, &#39;wuvxyz&#39;] 
字符串Together_CZ逆序为： 
[&#39;ZC_rehtegoT&#39;, &#39;ZC_rehtegoT&#39;, &#39;ZC_rehtegoT&#39;, &#39;ZC_rehtegoT&#39;, &#39;ZC_rehtegoT&#39;, &#39;ZC_rehtegoT&#39;]

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