sort() doesn't work on dist.keys() ?
Fredrik Lundh
fredrik at pythonware.com
Thu Jul 10 16:49:06 EDT 2003
Steve Pinard wrote:
> New to Python, so please bear with me.
>
> >>> import sys
> >>> print sys.modules.keys() # works fine
> ['code', ...snip... ]
> >>> print sys.modules.keys().sort() # returns None, why?
> None
>
> According to my reference (Nutshell), keys() returns a
> "copy" of the dict keys as a list, so I would expect when
> I aply sort() to that list, I would get an in-place sorted
> version of that list. Why do I get None?
because sort returns None, not a reference to the list.
see the FAQ for details:
http://www.python.org/doc/FAQ.html#6.20
to fix this, use the return key:
keys = sys.modules.keys()
keys.sort()
print keys
</F>
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