[Python-Dev] any support for a methodcaller HOF?

Alex Martelli aleaxit at gmail.com
Fri Feb 3 15:35:02 CET 2006

On Feb 3, 2006, at 1:36 AM, Michael Hudson wrote:

> Alex Martelli <aleaxit at gmail.com> writes:
>> I was recently reviewing a lot of the Python 2.4 code I have written,
>> and I've noticed one thing: thanks to the attrgetter and itemgetter
>> functions in module operator, I've been using (or been tempted to  
>> use)
>> far fewer lambdas, particularly but not exclusively in key= arguments
>> to sort and sorted.
> Interesting.  Something I'd noticed was that *until* the key= argument
> to sort appeared, I was hardly using any lambdas at all (most of the
> places I had used them were rendered obsolete by list comprehensions).

Mine too, but many new places appeared, especially in itertools.

> A class I wrote (and lost) ages ago was a "placeholder" class, so if
> 'X' was an instance of this class, "X + 1" was roughly equivalent to
> "lambda x:x+1" and "X.method(zip, zop)" was roughly equivalent to your
> "methodcaller("method", zip, zop)".  I threw it away when listcomps
> got implemented.  Not sure why I mention it now, something about your
> post made me think of it...

Such a placeholder would certainly offer better syntax and more power  
than methodcaller (and itemgetter and attrgetter, too).  A lovely idea!


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