On Apr 3, 11:02 am, Alain Ketterlin <al...@dpt-info.u-strasbg.fr> wrote: > python <w.g.sned...@gmail.com> writes: > > tag23gr is a list of lists each with two items. > > g23tag is an empty dictionary when I run the for loop below. > > When is is complete each key is a graphic name who's values are a list > > of tags. > > > for item in tag23gr: > > ... value, key = tuple(item) > > ... if(g23tag.get(key)): > > ... g23tag[key].append(value) > > ... else: > > ... g23tag[key] = [value] > > for item in tag23gr: > g23tag.setdefault(item[0],[]).append(item[1]) > > -- Alain.
Or alternatively: from collections import defaultdict g23tag = defaultdict(list) for item in tag23gr: ....g23tag[item[0]].append(item[1]) -- http://mail.python.org/mailman/listinfo/python-list
