Python异常处理 [英] Python Exception handling

问题描述

C有perror和errno，打印并存储遇到的最后一个错误。执行文件io时，这是很方便的，因为我不需要fstat（）每个失败的文件作为fopen（）的参数来呈现给用户调用失败的原因。

C has perror and errno, which print and store the last error encountered. This is convenient when doing file io as I do not have to fstat() every file that fails as an argument to fopen() to present the user with a reason why the call failed.

我想知道在正确处理python中的IOError异常时抓取errno的正确方法是什么？

I was wondering what is the proper way to grab errno when gracefully handling the IOError exception in python?

In [1]: fp = open("/notthere")
---------------------------------------------------------------------------
IOError                                   Traceback (most recent call last)

/home/mugen/ in ()

IOError: [Errno 2] No such file or directory: '/notthere'


In [2]: fp = open("test/testfile")
---------------------------------------------------------------------------
IOError                                   Traceback (most recent call last)

/home/mugen/ in ()

IOError: [Errno 13] Permission denied: 'test/testfile'


In [5]: try:
   ...:     fp = open("nothere")
   ...: except IOError:
   ...:     print "This failed for some reason..."
   ...:     
   ...:     
This failed for some reason...

推荐答案

异常有一个 errno 属性：

try:
    fp = open("nothere")
except IOError as e:
    print(e.errno)
    print(e)

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