[Python-Dev] any support for a methodcaller HOF? (original) (raw)

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!

Alex

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