反转字符串的前半部分和后半部分并将它们 return 在一起

Question

我如何定义一个将字符串分成两部分并将它们反转的函数？如果字符串是奇数，则保留中间字符（余数）。

例如：

revStr(“ “)
revStr(“xy“)
revStr(“wxyz“)
revStr(“vwxyz“)
revStr(“uvwxyz“)
revStr(“tuvwxyz”)

会输出：


xy
xwzy
wvxzy
wvuzyx
vutwzyx

我已经试过了，但我什至无法正确翻转偶数字符串...

def revStr(string):
    output = " "
    start = 0 
    if len (string) % 2 == 0:
        x = string[start:start//2] 
        y = x[::-1]
        string = x+y
    return(string)
    
printrevStr("abcdef")

为此需要一些指导或想法，在此先感谢！如果有什么我可以澄清的，请告诉我。

Answer 1

import math

def revStr(string):
    half = len(string) / 2
    string = string[:math.floor(half):][::-1] + string[math.floor(half):math.ceil(half):] + string[math.ceil(half)::][::-1]
    return (string)

print(revStr("abcde"))
print(revStr("abde"))

Answer 2

def rev_str(string):
    mid_point = len(string) // 2
    if len(string) % 2 == 0:
        return string[0:mid_point][::-1] + string[mid_point:][::-1]
    else:
        return string[0:mid_point][::-1] + string[mid_point] + string[mid_point + 1:][::-1]


if __name__ == '__main__':
    print(rev_str(" "))
    print(rev_str("xy"))
    print(rev_str("wxyz"))
    print(rev_str("vwxyz"))
    print(rev_str("uvwxyz"))
    print(rev_str("tuvwxyz"))

输出：

 
xy
xwzy
wvxzy
wvuzyx
vutwzyx

Answer 3

你搞砸的是中间索引部分和两半。在这里你可以做的是取一个中间索引 value=len//2 并取一半，这样一半到中间，另一半从中间索引开始。一旦你有了两半，你可以简单地使用 x[::-1] 等反向打印它们

def revStr(string):
    mid=len(string)//2
    if len(string)%2 != 0:
        x=string[:mid]
        middle=string[mid]
        y=string[mid+1:]
        print(x[::-1],middle,y[::-1],sep='')
    else:
        x=string[:mid]
        y=string[mid:]
        print(x[::-1],y[::-1],sep='')

revStr("abcdef")

Answer 4

import re

def revStr(keyword):
    if len(keyword) <= 2:
        return keyword
        
    keyword = [val.group()[::-1] for num,val in enumerate(re.finditer(r"(.){2}",keyword), start=1)]
    return ''.join(map(str, keyword))

Answer 5

def reverse_string(string):
    length = len(string)
    
    mid = length//2
    # seperating in 3 parst
    first_half, second_half, middle = None, None, None
    
    # seperating string into first half, second half and mid based on length
    if length%2==1:
        first_half = string[:mid]
        second_half = string[mid+1:]
        middle = string[mid]
    else:
        first_half = string[:mid]
        second_half = string[mid:]
        
    # reversing the first half and second half
    first_half_reverse = first_half[::-1]
    second_half_reverse = second_half[::-1]
    
    # assembling the final result together
    final_result = None
    if middle is not None:
        final_result = first_half_reverse + middle + second_half_reverse
    else:
        final_result = first_half_reverse + second_half_reverse
    
    return final_result

反转字符串的前半部分和后半部分并将它们 return 在一起

reverse first & second halves of string and return them together

python

string

slice

python-3.x