nested looping

PK superprad at gmail.com
Thu Apr 9 00:45:37 CEST 2009


Excellent! Thanks all. Since I need to have this running on python 2.4 as
well, I think I'll choose,

for alpha in alist:
   for xy in xlist:
        if alpha+xy in checklist:
           break
   else:
       missing.append(alpha)

jus tested and worked like a charm.

Appreciate your help!!



On Wed, Apr 8, 2009 at 6:12 PM, Luis Alberto Zarrabeitia Gomez
<kyrie at uh.cu>wrote:

>
> Quoting PK <superprad at gmail.com>:
>
> > So I'm trying to see whats the cleanest way to do this:
> >
> > I have a
> >
> > checklist = [ax, bx, by, cy  ..] (a combination of a,b,c with x and y,
> > either both on one)
> >
> > allist = [a,b,c,....]
> > xlist = [x, y, ..]
> >
> [...]
> > now the problem is I want to include alpha in missing list only if
> > none of the combinations from xlist with alpha are in checklist.
>
> This is untested:
>
> for alpha in alist:
>    for xy in xlist:
>         if alpha+xy in checklist:
>            break
>    else:
>        missing.append(alpha)
>
> (note that the "else" is for the "for", not the "if")
>
> You could also try the any/all functions from python2.5:
>
> for alpha in alist:
>    if not any(alpha + xy in checklist for xy in xlist):
>        missing.append(alpha)
>
>
> Or the really not recommended one-liner:
>
> missing = [alpha for alpha in alist if not any(alpha + xy in checklist for
> xy in
> xlist)]
>
> (remember, all of this is untested)
>
> --
> Luis Zarrabeitia
> Facultad de Matemática y Computación, UH
> http://profesores.matcom.uh.cu/~kyrie<http://profesores.matcom.uh.cu/%7Ekyrie>
>
>
> --
> Participe en Universidad 2010, del 8 al 12 de febrero de 2010
> La Habana, Cuba
> http://www.universidad2010.cu
>
>
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