[Haskell-cafe] Why is there no "splitSeperator" function in Data.List

Iustin Pop iusty at k1024.org
Sun Feb 13 11:29:26 CET 2011


On Sun, Feb 13, 2011 at 06:01:01PM +0800, Lyndon Maydwell wrote:
> Does the Python implementation operate on Strings, or all lists?

Of course, just on strings.

> I think this could be quite important as many split implementations
> take regular expressions as arguments. This could be quite challenging
> for general lists.

Agreed. But (in Python at least), split via re and split via (static)
element are two separate functions, and split via element can be nicely
replicated in Haskell.

regards,
iustin

> That said, I would like to see some of these features in the split package.
> 
> On Sun, Feb 13, 2011 at 5:50 PM, Iustin Pop <iusty at k1024.org> wrote:
> > On Sat, Feb 12, 2011 at 11:21:37AM -0500, Gwern Branwen wrote:
> >> On Sat, Feb 12, 2011 at 11:00 AM, Robert Clausecker <fuzxxl at gmail.com> wrote:
> >> > Is there any reason, that one can't find a function that splits a list
> >> > at a seperator in the standard library? I imagined something like this:
> >> >
> >> >
> >> >    splitSeperator :: Eq a => a -> [a] -> [[a]]
> >> >
> >> >    splitSeperator ',' "foo,bar,baz"
> >> >      --> ["foo","bar","baz"]
> >> >
> >> > Or something similar? This is needed so often, even if I can implement
> >> > it in one line, is there any reason why it's not in the libs?
> >>
> >> See http://hackage.haskell.org/package/split
> >>
> >> The reason it's not in Data.List is because there are a bazillion
> >> different splits one might want (when I was pondering the issue before
> >> Brent released it, I had collected something like 8 different proposed
> >> splits), so no agreement could ever be reached.
> >
> > It is curious though that the Python community managed to agree on a
> > single implementation and include that in the standard library… So it is
> > possible :)
> >
> > I also needed a split function and ended up with coding one that behaves
> > like the Python one for my project.
> >
> > regards,
> > iustin
> >
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> >



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