seek operation in python

Chris Angelico rosuav at gmail.com
Thu Apr 30 09:33:25 CEST 2015


On Thu, Apr 30, 2015 at 4:27 PM, Cecil Westerhof <Cecil at decebal.nl> wrote:
>> with open("input.cpp") as f:
>> lines = f.readlines()
>> print(lines[7])
>
> Is the following not better:
>     print(open('input.cpp', 'r').readlines()[7])
>
> Time is the same (about 25 seconds for 100.000 calls), but I find this
> more clear.

The significant difference is that the 'with' block guarantees to
close the file promptly. With CPython it probably won't make a lot of
difference, and in a tiny script it won't do much either, but if you
do this on Jython or IronPython or MicroPython or some other
implementation, it may well make a gigantic difference - your loop
might actually fail because the file's still open.

ChrisA



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