在python c = pickle.load(open(fileName，'r'))中是否关闭文件? [英] In python c = pickle.load(open(fileName, 'r')) does this close the file?

问题描述

我尝试使用Google，但找不到答案.

I tried to Google but cannot find an answer.

如果我愿意

c = pickle.load(open(fileName, 'r'))

此操作后文件会自动关闭吗?

Will the file be automatically closed after this operation?

推荐答案

否，但是您可以简单地对其进行修改以关闭文件:

No, but you can simply adapt it to close the file:

# file not yet opened
with open(fileName, 'r') as f:
    # file opened
    c = pickle.load(f)
    # file opened
# file closed

with语句的作用是(除其他外)调用with语句中列出的对象的__exit__()方法(在本例中为打开的文件)，在这种情况下将关闭文件.

What with statement does, is (among other things) calling __exit__() method of object listed in with statement (in this case: opened file), which in this case closes the file.

关于打开文件的__exit__()方法:

>>> f = open('deleteme.txt', 'w')
>>> help(f.__exit__)
Help on built-in function __exit__:

__exit__(...)
    __exit__(*excinfo) -> None.  Closes the file.

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