Python实现字符串反转的6种方法

1.使用字符串切片

>>> s = "python"
>>> s[::-1]
'nohtyp'
>>>

2.使用列表的reverse方法

>>> s = "python"
>>> lst = list(s)
>>> lst.reverse()
>>> "".join(lst)
'nohtyp'
>>>

手写 reverse

>>> def reverseString(s:str) -> str:
    lst = list(s)
    i, j = 0, len(s)-1
    while i < j:
        lst[i], lst[j] = lst[j], lst[i]
        i , j = i + 1, j - 1
    return "".join(lst)
 
>>> s = 'python'
>>> reverseString(s)
'nohtyp'
>>>

3.使用reduce

>>> from functools import reduce  # Python3 中不可以直接调用reduce
>>> s = "python"
>>> reduce(lambda x, y: y+x, s)
'nohtyp'
>>>

reduce 函数帮助：

>>> help(reduce)
Help on built-in function reduce in module _functools:
 
reduce(...)
    reduce(function, sequence[, initial]) -> value
     
    Apply a function of two arguments cumulatively to the items of a sequence,
    from left to right, so as to reduce the sequence to a single value.
    For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates
    ((((1+2)+3)+4)+5).  If initial is present, it is placed before the items
    of the sequence in the calculation, and serves as a default when the
    sequence is empty.
 
>>>

4.使用递归函数

>>> def reverse(s):
    if s == "":
        return s
    else:
        return reverse(s[1:]) + s[0]
 
     
>>> reverse('python')
'nohtyp'
>>>

python中默认的最大递归数：

>>> import sys
>>> sys.getrecursionlimit()
1000
>>>

5.使用栈

>>> def rev(s):
    lst = list(s) # 转换成list
    ret = ""
    while len(lst):
        ret += lst.pop() # 每次弹出最后的元素
    return ret
#Python小白学习交流群：711312441 
>>> s = 'python'
>>> rev(s)
'nohtyp'
>>>

6.for循环

>>> def rever(s):
    ret = ""
    for i in range(len(s)-1, 0, -1):
        ret += s[i]
    return ret
 
>>> s = "python"
>>> rev(s)
'nohtyp'
>>> 

到此这篇关于Python实现字符串反转的6种方法的文章就介绍到这了,更多相关内容请搜索服务器之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持服务器之家！

原文地址：https://blog.csdn.net/Python_222/article/details/130108777