The Python standard library and PEP8

Emmanuel Surleau emmanuel.surleau at
Sun Apr 19 20:41:02 CEST 2009

On Sunday 19 April 2009 19:37:59 Gabriel Genellina wrote:
> En Sun, 19 Apr 2009 13:43:10 -0300, Emmanuel Surleau
> <emmanuel.surleau at> escribió:
> > Exploring the Python standard library, I was surprised to see that
> > several
> > packages (ConfigParser, logging...) use mixed case for methods all over
> > the
> > place. I assume that they were written back when the Python styling
> > guidelines were not well-defined.
> The name policy changed in March 2004. Before that, PEP8 said:
>      Function Names
>        Plain functions exported by a module can either use the CapWords
>        style or lowercase (or lower_case_with_underscores).  There is
>        no strong preference, but it seems that the CapWords style is
>        used for functions that provide major functionality
>        (e.g. nstools.WorldOpen()), while lowercase is used more for
>        "utility" functions (e.g. pathhack.kos_root()).
> The current version says:
>      Function Names
>        Function names should be lowercase, with words separated by
> underscores
>        as necessary to improve readability.
>        mixedCase is allowed only in contexts where that's already the
>        prevailing style (e.g., to retain backwards
> compatibility.

Ah, that makes sense.

> > Given that it's rather irritating (not to mention violating the
> > principle of
> > least surprise) to have this inconsistency, wouldn't it make sense to
> > clean
> > up the API by marking old-style, mixed-case methods as deprecated (but
> > keep them around anyway) and add equivalent methods following the
> > lowercase_with_underscores convention?
> The threading module has such aliases, but there are no plans for mass
> renaming all the stdlib that I know of. You'll have to live with this
> inconsistency.


> > On an unrelated note, it would be *really* nice to have a length
> > property on
> > strings. Even Java has that!

> Why would it be nice to have? I never missed it...

First off, it's pretty commonplace in OO languages. Secondly, given the 
number of methods available for the string objects, it is only natural to 
assume that dir("a") would show me a len() or length() or size() method. 
Having to use a function for such a mundane operation feels unnatural and 
not OO.



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