使用Ipython退出脚本时不调用atexit函数 [英] atexit function is not called when exiting the script using Ipython

问题描述

下面是用脚本写的代码，例如test_atexit.py

Below is the code written in a script say test_atexit.py

def exit_function():
    print "I am in exit function"
import atexit
atexit.register(exit_function)
print "I am in main function"

当我使用python2.4运行函数时，调用exit_function

When i run the function using python2.4 then exit_function is being called

$python2.4 test_atexit.py  
I am in main function  
I am in exit function

当我使用ipython运行相同时，则不调用exit_function

When i run the same using ipython then exit_function is not being called

$ ipython  
In [1]: %run test_atexit.py  
I am in main function  
In [2]: 

为什么在使用Ipython运行脚本时不调用exit_function以及如何让ipython调用exit_function

why exit_function is not called when running script using Ipython and how can i make ipython to call exit_function

推荐答案

atexit 函数在Python解释器退出时调用，而不是在脚本完成时调用。当您在IPython中％运行时，解释器仍在运行，直到您退出IPython。当你这样做时，你应该看到 exit_function（）的输出。

atexit functions are called when the Python interpreter exits, not when your script finishes. When you %run something in IPython, the interpreter is still running until you quit IPython. When you do that, you should see the output from your exit_function().

可能你想要的是一个try / finally，它确保在try块之后运行finally代码，即使发生异常：

Possibly what you want is a try/finally, which ensures that the finally code is run after the try block, even if an exception occurs:

try:
    print("Doing things...")
    raise Exception("Something went wrong!")
finally:
    print("But this will still happen.")

如果你真的需要运行atexit函数，那么你可以调用 atexit._run_exitfuncs 。然而，这是没有记录的，它可能会做出意想不到的事情，因为任何东西都可以注册atexit函数 - IPython本身就会注册6个，所以如果你在IPython中这样做，你很可能会破坏它。

If you really need to make atexit functions run, then you can call atexit._run_exitfuncs. However, this is undocumented, and it may do unexpected things, because anything can register atexit functions - IPython itself registers half a dozen, so you're likely to break things if you do it in IPython.

（另外，Python 2.4？对于各地开发人员的理智，如果可以升级，请这样做;-)）

(Also, Python 2.4? For the sanity of developers everywhere, if it's possible to upgrade, do so ;-) )

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