Python 字符串加减运算：自定义 MyStr 类实现字符串的增删操作

class MyStr(str):
    def __init__(self, s):
        self.s = s

    def __add__(self, other):
        res = ''
        for c in self.s:
            if c not in other:
                res += c
        return MyStr(res + other)

    def __sub__(self, other):
        res = ''
        for c in self.s:
            if c not in other:
                res += c
        return MyStr(res)

    def __repr__(self):
        return self.s

s1 = input()
s2 = input()

s1 = MyStr(s1)
s2 = MyStr(s2)

print(s1 + s2)
print(s1 - s2)

示例输入：

abcdefg
acdi

示例输出：

abcdefgi
befg