I have this type of situation and wonder if I should use a global variable outside the recursive function instead of passing the updated parameter through.
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? thanks, --Tim -- https://mail.python.org/mailman/listinfo/python-list