Question

I have a question about sort defaultdict in python

Assume I have the following codes:

a = defaultdict(defaultdict)
a['c']['C'] = 1
a['b']['B'] = 2
a['a']['A'] = 3
a['a']['AA'] = 4

I’d like to sort it by the first key and then get another sorted defaultdict like

a['a']['A'] = 3
a['a']['AA'] = 4
a['b']['B'] = 2
a['c']['C'] = 1

I’ve tried using sorted(a.iteritems()) and then get another list. However I need to get dict because I have to iter them.

How can I do this?

Answer 1

for k1 in sorted(a.keys()):
   sub = a[k1]
   for k2 in sorted(sub.keys()):
     print k1, k2, sub[k2] # or do whatever else

This prints the keys and values sorted as you want.