On Wed, 22 Oct 2008 10:12:56 -0700, bearophileHUGS wrote: > Frank Niemeyer: >> There's simply no >> way to increment a non-existent value - not without performing some >> obscure implict behind-the-scenes stuff. > > Like importing and using a defaultdict(int). > > >> > So you >> > either have to use a workaround: >> >> > >>> try: >> > ... counter['B'] += 1 >> > ... except KeyError: >> > ... counter['B'] = 1 >> >> Or you could simply use >> >> if counter.has_key('B'): >> counter['B'] += 1 >> else: >> counter['B'] = 1 > > Both those are slow. Better to use: > > if 'B' in counter: > counter['B'] += 1 > else: > counter['B'] = 1 > > Or with a defaultdict: > > counter = defauldict(int) > counter['B'] += 1
Or: counter['B'] = counter.get('B', 0) + 1 Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list