Steven D'Aprano wrote:
>On Sun, 20 Nov 2005 11:05:53 +0800, Xiao Jianfeng wrote:
>
>
>
>> I have some other questions:
>>
>> when "fh" will be closed?
>>
>>
>
>When all references to the file are no longer in scope:
>
>def handle_file(name):
> fp = file(name, "r")
> # reference to file now in scope
> do_stuff(fp)
> return fp
>
>
>f = handle_file("myfile.txt)
># reference to file is now in scope
>f = None
># reference to file is no longer in scope
>
>At this point, Python *may* close the file. CPython currently closes the
>file as soon as all references are out of scope. JPython does not -- it
>will close the file eventually, but you can't guarantee when.
>
>
>
>> And what shoud I do if I want to explicitly close the file immediately
>>after reading all data I want?
>>
>>
>
>That is the best practice.
>
>f.close()
>
>
>
>
Let me introduce my problem I came across last night first.
I need to read a file(which may be small or very big) and to check line
by line
to find a specific token, then the data on the next line will be what I
want.
If I use readlines(), it will be a problem when the file is too big.
If I use "for line in OPENED_FILE:" to read one line each time, how can
I get
the next line when I find the specific token?
And I think reading one line each time is less efficient, am I right?
Regards,
xiaojf
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