On Oct 4, 4:35 pm, Gary Coulbourne <[EMAIL PROTECTED]> wrote:
> >>> dict1={1: 4, 3: 5}... and 2 millions element
> >>> dict2={3: 3, 8: 6}... and 3 millions element
>
> If you don't mind doing some kind of lazy evaluation, you could do
> something like...
>
> ------------------------------
> dict1={1:4, 3:5}
> dict2={3:3, 8:6}
>
> import UserDict
>
> class Merge(UserDict.DictMixin):
>
> def __init__(self,d1,d2):
> self.dict1 = d1
> self.dict2 = d2
>
> keyset = set(d1.keys())
> keyset.update(d2.keys())
>
> self.dkeys = list(keyset)
>
> def keys(self):
> return self.dkeys
>
> def __getitem__(self,key):
> v1 = 0
> v2 = 0
> if key in self.dict1:
> v1 = self.dict1[key]
> if key in self.dict2:
> v2 = self.dict2[key]
> return v1+v2
Generalising to support any number of dicts reduces the amount of code
somewhat:
import UserDict
class Merge(UserDict.DictMixin):
def __init__(self, *args):
self._dicts = args
self._keys = list(set(k for d in self._dicts for k in d))
def keys(self):
return self._keys
def __getitem__(self, key):
return sum(d.get(key, 0) for d in self._dicts)
--
Paul Hankin
--
http://mail.python.org/mailman/listinfo/python-list
