python字符串操作练习

Python字符串操作练习题可以包括判断回文字符串、反转字符串、字符串变形（字母大小写切换）以及找到最长回文子串等任务。下面是几个例子：

1. 判断回文字符串（双指针）：

class Solution:
    def judge(self, s: str) -> bool:
        left = 0
        right = len(s) - 1
        while left < right:
            if s[left != s[right]:
                return False
            left += 1
            right -= 1
        return True

2. 反转字符串：

class Solution:
    def reverse(self, s: str) -> str:
        return s[::-1]

3. 字符串变形（字母大小写切换）：

class Solution:
    def transform(self, s: str) -> str:
        transformed = ""
        for char in s:
            if char.islower():
                transformed += char.upper()
            elif char.isupper():
                transformed += char.lower()
            else:
                transformed += char
        return transformed

4. 找到最长回文子串：

class Solution:
    def longestPalindrome(self, s: str) -> str:
        longest = ""
        for i in range(len(s)):
            for j in range(len(s), i, -1):
                substring = s[i:j]
                if substring == substring[::-1 and len(substring) > len(longest):
                    longest = substring
        return longest