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
Bye,
bearophile
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