x = "12@12" y = "12&12" class WoCao: def wocao(self,exp): if '@' in exp: index = exp.index('@') a = eval(exp[0:index]) b = eval(exp[index+1:]) return a * b elif '&' in exp: index = exp.index('&') a = eval(exp[0:index]) b = eval(exp[index+1:]) return a + b wc = WoCao() print(wc.wocao(x)) print(wc.wocao(y))