'''
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。
'''

# -*- coding:utf-8 -*-
class Solution:
    # s 源字符串
    def replaceSpace(self, s):
        # write code here
        res = []
        for ch in s:
            if ch == " ":
                res.append("%20")
            else:
                res.append(ch)
        return ''.join(res)

if __name__ == "__main__":
    s = "We are happy"
    res = Solution().replaceSpace(s)
    print(res)