在Python中使用输入参数抛出自定义异常以进行打印

Question

我已经看到了几个类似this ， this和this的示例，它们展示了如何在Python中引发自定义异常。 但是我希望完成的事情是这样的：

## in main.py
import my_errors

if  os.path.exists(filename):
    # here, I'd like to pass in 'filename' as parameter to FileNotFound
    raise my_errors.FileNotFound(filename)

## in my_errors.py
class MyError(Exception):
    pass

class FileNotFound(MyError):
    # here, how do I make this FileNotFound class to accept/receive 'filename' as parameter so that I can print something informative like below
    print("FileNotFound ERROR: Please make sure that the following file exists:", filename)

预先感谢您的帮助！

Answer 1

您将要实现自己的__init__()函数。

class FileNotFound(MyError):

    def __init__(self, filename):
        super().__init__("FileNotFound ERROR: Please make sure that the following file exists:" % filename)

请注意，这将设置异常的错误消息。 正常打印：

class FileNotFound(MyError):

    def __init__(self, filename):
        print("FileNotFound ERROR: Please make sure that the following file exists:", filename)

        super().__init__(filename)