Strategy for determing difference between 2 very large dictionaries

[bearophileHUGS at lycos.com]

Peter Otten:
> >>> a = dict(a=1, b=2, c=3)
> >>> b = dict(b=2, c=30, d=4)
> >>> dict(set(a.iteritems()) ^ set(b.iteritems()))

For larger sets this may be better, may avoid the creation of the
second set:

dict(set(a.iteritems()).symmetric_difference(b.iteritems()))

Bye,
bearophile