一、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。

二、代码实现

方法一、书上的方法

# -*- coding:utf-8 -*-
class Solution:
    # s 源字符串
    def replaceSpace(self, s):
        # write code here
        spacenumber = 0
        for char in s:
            if char == ' ': spacenumber = spacenumber + 1
        result_len = len(s) + spacenumber * 3
        new_s = ['' for i in range(result_len)]
        for char in s[::-1]:
            if char == " ":
                new_s[result_len-2:result_len] = "%20"
                result_len = result_len - 3
            else:
                new_s[result_len-1] = char
                result_len = result_len - 1
        return ''.join(new_s)

方法二、python技巧

# -*- coding:utf-8 -*-
class Solution:
    # s 源字符串
    def replaceSpace(self, s):
        # write code here
        s = s.replace(" ", "%20")
        return s