[issue11303] b'x'.decode('latin1') is much slower than b'x'.decode('latin-1')

[Alexander Belopolsky]

Alexander Belopolsky <belopolsky at users.sourceforge.net> added the comment:

On Thu, Feb 24, 2011 at 11:01 AM, Marc-Andre Lemburg
<report at bugs.python.org> wrote:
..
> On this ticker, we're discussing just one application area: that
> of the builtin short cuts.
>
Fair enough.  I was hoping to close this ticket by simply committing
the posted patch, but it looks like people want to do more.  I don't
think we'll get measurable performance gains but may improve code
understandability.

> To have more encoding name variants benefit from the optimization,
> we might want to enhance that particular normalization function
> to avoid having to compare against "utf8" and "utf-8" in the
> encode/decode functions.

Which function are you talking about?

1. normalize_encoding() in unicodeobject.c
2. normalizestring() in codecs.c

The first is s.lower().replace('-', '_') and the second is
s.lower().replace(' ', '_'). (Note space vs. dash difference.)

Why do we need both?  And why should they be different?

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title: b'x'.decode('latin1') is much slower than	b'x'.decode('latin-1') -> b'x'.decode('latin1') is much slower than b'x'.decode('latin-1')

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<http://bugs.python.org/issue11303>
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