bit late here, but if it's as simple as you say, i think it would be much more efficient (because you only scan checklist and alist once each) to do:
known = set() for check in checklist: known.add(check[0:-1]) missing = filter(lambda alpha: alpha not in known, alist) andrew PK wrote: > 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 > <ky...@uh.cu>wrote: > >> >> Quoting PK <superp...@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 >> >> > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
