[Python-Dev] Iterable String Redux (aka StringABC) (original) (raw)

Ron Adam rrr at ronadam.com
Fri May 30 17:50:08 CEST 2008

Raymond Hettinger wrote:

"Jim Jewett"

It isn't really stringiness that matters, it is that you have to terminate even though you still have an iterable container. Well said.

Guido had at least a start in Searchable, back when ABC were still in the sandbox: Have to disagree here. An object cannot know in general whether a flattener wants to split it or not. That is an application dependent decision. A better answer is be able to tell the flattener what should be considered atomic in a given circumstance. Raymond

A while back (a couple of years I think), we had a discussion on python-list about flatten in which I posted the following version of a flatten function. It turned out to be nearly twice as fast as any other version.

def flatten(L): """ Flatten a list in place. """ i = 0 while i < len(L): while type(L[i]) is list: L[i:i+1] = L[i] i += 1 return L

For this to work the object to be flattened needs to be both mutable and list like. At the moment I can't think of any reason I would want to flatten anything that was not list like.

To make it a bit more flexible it could be changed just a bit.

def flatten(L): """ Flatten a list in place. """ objtype = type(L) i = 0 while i < len(L): while type(L[i]) is objtype: L[i:i+1] = L[i] i += 1 return L

Generally, I don't think you would want to flatten dissimilar objects.

Cheers, Ron

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