[Python-ideas] Rehabilating reduce (as "fold")

Fri Jul 12 21:49:55 CEST 2013

On 07/12/2013 01:01 AM, Nick Coghlan wrote:
> Efficiently merging a collection of iterables into a list would then just be:
>> data = fold(operator.iadd, [], iterables)
>> I'd personally be in favour of the notion of also allowing strings as the
> first argument, so you could instead write:
>> data = fold("+=", [], iterables)
>>> This could also be introduced as an alternative API in functools.

How about if start was first... and could take a class?
 data = fold(class, op, iterables)
 data = fold(instance, op, iterables)
> (Independent of this idea, it would actually be nice if the operator module
> had a dictionary mapping from op symbols to names, like
> operator.by_symbol["+="] giving operator.iadd)

I'm guessing that this is how that might be used?
 name = operator.symbols['+=']
 op_method = start.__getattribute__(name)
Looks good to me. +1
Cheers,
 Ron