with open('com1', 'r') as f:

Terry Reedy tjreedy at udel.edu
Sun Apr 5 08:48:20 CEST 2009

Lawrence D'Oliveiro wrote:
> In message <91e09eaf-5a25-4a6b-b131-
> a5245970b337 at f19g2000yqh.googlegroups.com>, gert wrote:
>> On Apr 4, 12:58 am, Lawrence D'Oliveiro <l... at geek-
>> central.gen.new_zealand> wrote:
>>> In message <8bc55c05-19da-41c4-
>>> b916-48e0a4be4... at p11g2000yqe.googlegroups.com>, gert wrote:
>>>> with open('com1', 'r') as f:
>>>> for line in f:
>>>>     print('line')
>>> Why bother, why not just
>>> for line in open('com1', 'r') :
>>>     print line
>> So its does the same thing as with right ?
> Why do you need a with?
>> Automatic closing and finalizing stuff.
> All Python objects are reference-counted.

Nope.  Only in CPython, and even that could change.

> Once the file object becomes 
> inaccessible, it is automatically closed. Simple.

Even in CPython, that would not be true now is the object became 
involved in or became a dependent of a reference cycle.

> Note: I wouldn't do this for files open for writing. I'd prefer to make sure 
> those were properly flushed and closed, if only to catch any I/O errors.


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