评估得到错误输出的后缀表达式

Question

示例测试用例 测试用例 1： 预期输出： 输入·后缀·表达式231*+9- 结果·of·后缀·表达式·231*+9-·is·-4

测试用例 2： 预期输出： 输入·后缀·表达式34+22/* 结果·of·后缀·表达式·34+22/*·is·7

    class Evaluate:
        def __init__(self, capacity):
            self.top = -1
            self.capacity = capacity
            self.array = []
            
        def isEmpty(self):
            return True if self.top == -1 else False
        
        def peek(self):
            return self.array[-1]
            
        def pop(self):
            if not self.isEmpty():
                self.top -= 1
                return self.array.pop()
            else:
                return "$"
                
        def push(self, op):
            self.top += 1
            self.array.append(op)
            
        def evaluatePostfix(self, exp):
            for i in exp:
                
                if i.isdigit():
                    self.push(i)
                    
                else:
                    val1 = self.pop()
                    val2 = self.pop()
                    self.push(str(eval(val2 + i + val1)))
                    
            return int(self.pop())
            
    exp = input('Enter Postfix expression')
    obj = Evaluate(len(exp))
    print("Result of Postfix expression", exp , "is %d" % (obj.evaluatePostfix(exp)))


Test Case 1: Getting Correct Output = Result·of·Postfix·expression·231*+9-·is·-4
But in Test Case 2: I will get an Error


**Please let me know Where iam wrong...**

Answer 1

我运行了你的代码，它似乎给了我7.0 用于测试用例 2，所以它似乎工作。但是，字符串格式无法将7.0 转换为整数（%d），所以我收到此错误：

Traceback (most recent call last):
  File "69147707.py", line 39, in <module>
    print("Result of Postfix expression", exp , "is %d" % (obj.evaluatePostfix(exp)))
  File "69147707.py", line 35, in evaluatePostfix
    return int(self.pop())
ValueError: invalid literal for int() with base 10: '7.0'

也许尝试使用 int() 将解决方案转换为 int？