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Python

Posted by James Ashdown
James Ashdown
13,676 Points

Will files opened in list comprehensions close automatically?

Given the following list comprehension:

[item for item in open('file.txt') if re.search('Hello', item)]

Will the file.txt file be closed automatically since Iā€™m not assigning the opened file to a variable? If not, how would I close the file within the list comprehension?

Thanks -James

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,468 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,468 Points

The file would be closed eventually in garbage collection.

Alternatively, you could run the comprehension within a with block to auto close at the end of the comprehension. 

with open('file.txt') as f:
    [item for item in f if re.search('Hello', item)]