runes: > d = {} > for k in data: > try: > d[k] += 1 > except: > d[k] = 1 > > for k,v in d.items(): > if v == 1: > print k
For this problem, if duplicated keys are common enough, this version is probably the faster. With this *different* problem, it seems that sometimes the faster solution is using "in": http://pyalot.blogspot.com/2005/04/dictionary-speed.html Bye, Bearophile -- http://mail.python.org/mailman/listinfo/python-list