【剑指offer】4-替换空格

题目描述：
请实现一个函数，将一个字符串中的每个空格替换成“%20”。例如，当字符串为We Are Happy.则经过替换之后的字符串为We%20Are%20Happy。

Python实现

class Solution:
    # s 源字符串
    def replaceSpace(self, s):
        s = s.split(' ')
        return '%20'.join(s)

class Solution1:
    # s 源字符串
    def replaceSpace(self, s):
        s = s.replace(' ','%20')
        return s

import re
class Solution2:
    def replaceSpace(self, s):
        # write code here
        s=re.sub(r" ","%20",s)