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Date: Tue, 3 Jan 2012 15:17:15 +0100
From: Stefan Krah <stefan-usenet@bytereef.org>
To: python-list@python.org
Subject: Re: .format vs. %
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:18409

Neil Cerutti <neilc@norwich.edu> wrote:
> > In the real-world telco benchmark for _decimal, replacing the
> > single line
> >
> >     outfil.write("%s\n" % t)
> >
> > with
> >
> >     outfil.write("{}\n".format(t))
> >
> > adds 23% to the runtime. I think %-style formatting should not
> > be deprecated at all.
>    
> When it becomes necessary, it's possible to optimize it by
> hoisting out the name lookups.
>    ...
>    outfil_write = outfil.write
>    append_newline = "{}\n".format
>    ...
>        outfil_write(append_newline(t))
>        ...

Did you profile this? I did, and it still adds 22% to the runtime.


Stefan Krah