Leetcode上有个练习题，也是面试经常会遇到的：请实现一个函数，把字符串 s 中的每个空格替换成"%20"

请实现一个函数，把字符串 s 中的每个空格替换成"%20"
输入：s = "We are happy."
输出："We%20are%20happy."

'''
请实现一个函数，把字符串 s 中的每个空格替换成"%20"。
输入：s = "We are happy."
输出："We%20are%20happy."
'''
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def replaceSpace(s: str) ->str:                  
    '''把字符串 s 中的每个空格替换成"%20"'''
    res = ''
    for i in s:
        if i != " ":
            res += i
        else:
            res += "%20"
    return res
if __name__ == '__main__':
    s = "We are happy."
    print(replaceSpace(s))

解决思路就是遍历字符串，判断为空格就替换为%20

python里面有个replace方法可以直接替换字符串

s = "We are happy."
print(s.replace(" ", "%20"))