Presumably an import is no faster or slower than opening a file?

tinnews at tinnews at
Mon Apr 7 15:05:20 CEST 2008

Paul McGuire <ptmcg at> wrote:
> On Apr 6, 8:41 am, tinn... at wrote:
> > I'm trying to minimise the overheads of a small Python utility, I'm
> > not really too fussed about how fast it is but I would like to
> > minimise its loading effect on the system as it could be called lots
> > of times (and, no, I don't think there's an easy way of keeping it
> > running and using the same copy repeatedly).
> >
> > It needs a configuration file of some sort which I want to keep
> > separate from the code, is there thus anything to choose between a
> > configuration file that I read after:-
> >
> >     f = open("configFile", 'r')
> >
> > ... and importing a configuration written as python dictionaries or
> > whatever:-
> >
> >     import myConfig
> >
> > --
> > Chris Green
> Chris -
> The question is less an issue of the file overhead (both must open a
> file, read its contents, and then close it) than what is done with the
> file contents afterwards.
> A config file containing .INI-style or whatever content will need to
> be parsed into Python data/objects, and likely use Python code to do
> so.  An import will use the Python compiler itself, using optimized
> compiled C code to do the parsing and data/object construction.  But I
> think you would only see the distinction in a config file of
> substantial size or complexity.  If you think this will make a
> substantial difference in performance, then code up a test case and
> time it.
> In general, I'd say that splitting performance hairs to tip a design
> choice one way or another is a misguided premature optimization.
I quite agree (about the splitting hairs bit that is), as I said
before I just wanted to check that I wasn't missing anything really
obvious and, thus, that there probably isn't much to choose between
the two approaches.  Therefore I'll decide which way to do it on the
basis of 'usability'.

Chris Green

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