On Friday, January 16, 2015 at 11:26:46 PM UTC+5:30, Chris Angelico wrote:
> On Sat, Jan 17, 2015 at 4:49 AM, Tim wrote:
> > I want to get a union of all the values that any 'things' key may have,
> > even in a nested dictionary (and I do not know beforehand how deep the
> > nesting might go):
> >
> > d = {'things':1, 'two':{'things':2}}
> >
> > def walk(obj, res):
> > if not hasattr(obj, 'keys'):
> > return set(), set()
> >
> > if 'things' in obj:
> > res.add(obj['things'])
> >
> > for k in obj:
> > walk(obj[k], res)
> >
> > return res
> >
> > walk(d, set()) # returns {1, 2}
> >
> > Is it better to use a global to keep track of the values or does it even
> > matter?
>
> I would use a parameter rather than a global, but I'd make the
> parameter optional:
>
> def all_keys(obj, accum=None):
> if accum is None: accum=set()
> if 'things' in obj:
> res.add(obj['things'])
> for val in obj.values():
> all_keys(val, accum)
> return all_keys
>
> ChrisA
I dont like the hardwired this. However keeping that...
def all_keys(obj):
if not isinstance(obj, type({})): return set()
return ((set([obj['things']]) if 'things' in obj else set()) |
set(v for s in obj.values() for v in all_keys(s)))
--
https://mail.python.org/mailman/listinfo/python-list
