[Python-ideas] reduce(func, seq, initial=0)

[Florian Bruhin]

* Steven D'Aprano <steve at pearwood.info> [2014-10-10 21:10:10 +1100]:
> On Fri, Oct 10, 2014 at 11:11:36AM +0200, Stephan Sahm wrote:
> > Hi folk,
> > 
> > I stumbled upon the builtin reduce function. It has an optional parameter
> > initial, however if trying to set it like
> > 
> > import operator as op
> > reduce(op.add, range(10), initial=0)
> > 
> > I get
> > 
> > TypeError: reduce() takes no keyword arguments
> > 
> > 
> > I think it would be really straightforward to also add keyword
> > possibilities, at least to the parameter initial.
> 
> Unfortunately, this is a limitation of many built-in functions and 
> methods, possibly the majority. E.g.:
> 
> 
> Help on built-in function getattr in module builtins:
> getattr(...)
>     getattr(object, name[, default]) -> value
> 
> 
> but:
> 
> py> getattr(None, name='spam', default=42)
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> TypeError: getattr() takes no keyword arguments
> 
> 
> I seem to recall that there was a reason for this, but I don't quite 
> remember what... searching the archives may give a clue.
> 
> Personally, I have no objections *in principle* to adding support for 
> keyword arguments to built-ins, but it will depend on the details of why 
> they weren't already supported.

FWIW, I'd also really like to see keyword arguments for these
builtins. I always have to keep myself from doing things like

    "foo bar	baz".split(count=1)

But as said, I suspect there is *some* reason this is not possible.

Florian

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