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I am running pylint for bug detection in my project and stumble on this warning. How can I fix this warning?

Thinh Le
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1 Answers1

18

suppose you are opening a file:

file_handle = open("some_file.txt", "r")
...
...
file_handle.close()

You need to close that file manually after required task is done. If it's not closed, then resource (memory/buffer in this case) is wasted.

If you use with in above example:

with open("some_file.txt", "r") as file_handle:
    ...
    ...

there is no need to close that file. Resource de-allocation automatically happens when you use with.

nobleknight
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  • IIRC, using `something = open("a").readlines()` should de-allocate the resource imediatelly, since it is no longer referenced? But pylint still has an issue with this – Mahrkeenerh Mar 11 '22 at 18:49
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    @Mahrkeenerh No, that will _not_ immediately de-allocate the resource. Even if a resource is no longer referenced, it may not be garbage-collected for some time, if ever. You should never wait until garbage collection to clean up resources. That's why you never override destructors in Python. – Ian Goldby Jun 24 '22 at 11:43