Fate of lambda, Functional Programming in Python...

John Roth newsgroups at jhrothjr.com
Sat Aug 21 15:22:18 CEST 2004


"Reinhold Birkenfeld" <reinhold-birkenfeld-nospam at wolke7.net> wrote in
message news:2on5k1FcjmvdU1 at uni-berlin.de...
> Jeff Sandys wrote:
>
> > | > > Hi,all
> > | > >    I have a list like [(id,string),...],for example:
> > | > >
> > | > >    [(1,'xxxxx'),(7,'ppppp'),(4,'gggggg'),...]
> > | > >
> > | > >    I want to sort this list according to the id of each element.
> > | > >    After sorting,the list will become:
> > | > >
> > | > >    [(1,'xxxxx'),(4,'gggggg'),(7,'ppppp')...]
> > | >
> > | > list.sort sorts tuples by first argument, then second &c. If you
> > want
> > | > a custom sort order, look at the decorate-sort-undecorate pattern.
> > |
> > |  Or if you want to sort only on your Id, use a lambda:
> > |  l.sort(lambda x,y: cmp(x[0],y[0]))
> > |
> > |  To force sorting on just the nth element of the tuples, replace 0
> > with
> > |  n in the above.
> > |
> >
> > I think that lambda should be unlimited and expanded.  It already has
> > the
> > colon, block delimiter, so allow lambda to be a multistatement and
> > multiline
> > indented block!
>
> So in what point exactly is this different from a def(), then?

def() is a statement. It can't be used in an expression. That's
the crux of the problem, and always has been the crux of
the problem.

John Roth

> Reinhold





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