Question

我正在尝试创建一个只处理错误的类。调用函数时，请使用class方法，这样，如果用户输入错误，错误处理类中的方法就会停止函数的执行。

using System;
using System.Collections.Generic;

public class Program
{
    public static void Main()
    {
        foreach(var i in GetCol()) {
            Console.WriteLine(i);
        }
    }

    private static List<int> GetCol() {
        Console.WriteLine("I have been called");

        return new List<int>(){1, 2, 3, 4};
    }
}

/* Output
I have been called
1
2
3
4 */

所以，我想要的输出是：

class Error(Exception):
    pass

class UserError(Error):
    def handle_even(number):
        try: number % 2 == 0    
        except: raise UserError.handle_even('error: odd number\n')
    def handle_odd(number):
        try: number % 2 != 0
        except: raise UserError.handle_odd('error: even number\n')


def take_even(number):
    print(number) #if user input is bad, this shouldn't execute

def take_odd(number):
    print(number) #if user input is bad, this shouldn't execute



take_even(UserError.handle_even(5)) # I expect this to print 'error: odd number'
take_odd(UserError.handle_odd(4)) # I expect this to print 'error: even number'

但是，我得到的输出是：

error: odd number
error: even number

Answer 1

try块不会生成异常，因为表达式评估为true / false，而且您的奇/偶校验逻辑也是错误的。

class Error(Exception):
    pass

class UserError(Error):
    @classmethod
    def handle_even(cls, number):
        if number % 2 != 0:
            raise Error('error: odd number\n')

        return number

    @classmethod
    def handle_odd(cls, number):
        if number % 2 == 0:
            raise Error('error: even number\n')

        return number


def take_even(number):
    print(number) # if user input is bad, this won't execute

def take_odd(number):
    print(number) # if user input is bad, this won't execute

# This will raise an 'Error' exception (error: odd number)
take_even(UserError.handle_even(5))

# This will raise an 'Error' exception (error: even number)
take_odd(UserError.handle_odd(4))

您可以像下面这样处理这些特定的Error异常：

try:
    take_even(UserError.handle_even(5))
except Error as e:
    print(e) # print 'error: odd number'

try:
    take_odd(UserError.handle_odd(4))
except Error as e:
    print(e) # print 'error: even number'

编辑： 根据@NathanVērzemnieks建议将方法更改为类方法。

如何在不将错误处理写入函数的情况下创建自定义错误处理类

1 个答案: