Find all Key-Elements by the same Value in Dicts

Question

I have question about Dictionaries in Python.

here it is:

I have a dict like dict = { \'abc\':\'a\', \'cdf\':\'b\', \'gh\':\'a\', \'fh\':\'g\', \'hfz\'

Answer 1

Here's a naive implementation. Someone with better Python skills can probably make it more concise and awesome.

dict = { 'abc':'a', 'cdf':'b', 'gh':'a', 'fh':'g', 'hfz':'g' }

new_dict = {}
for pair in dict.items():
    if pair[1] not in new_dict.keys():
        new_dict[pair[1]] = []

    new_dict[pair[1]].append(pair[0])

print new_dict

This produces

{'a': ['abc', 'gh'], 'b': ['cdf'], 'g': ['fh', 'hfz']}