list organization question
Arnaud Delobelle
arnodel at googlemail.com
Thu Dec 11 18:31:03 EST 2008
Robocop <bthayre at physics.ucsd.edu> writes:
> I have a list of objects, each object having two relevant attributes:
> date and id. I'd like not only organize by id, but also by date.
> I.e. i would like to parse my list into smaller lists such that each
> new mini-list has a unique date, but consists of only objects with a
> specific id. Are there any handy imports i could use to accomplish
> something like this? I'm relatively new to python and as such don't
> know all of the preloaded functions at my disposal. Thanks for any
> help in advance, the community here is always ridiculously helpful.
Look at itertools.groupby.
E.g.
from itertools import groupby
data = [ my objects ]
def getdate(x): return x.date
by_date = {}
for date, objs in groupby(sorted(data, key=getdate), getdate):
by_date[date] = list(objs)
# list(objs) is the list of all objects in data whose date is date
I'm sorry if this is a bit terse...
--
Arnaud
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