Group dictionary key values in python

Here is a tutorial for group list of dictionary by dictionary key values.

First you needs to sort your list of dictionaries.

For Ex.

animals = [{'name': 'cow', 'size': 'large'},
           {'name': 'bird', 'size': 'small'},
           {'name': 'fish', 'size': 'small'},
           {'name': 'rabbit', 'size': 'medium'},
           {'name': 'pony', 'size': 'large'},
           {'name': 'squirrel', 'size': 'medium'},
           {'name': 'fox', 'size': 'medium'}] 

Here is my list of dictionary.
To sort lits of dictionary you can use following code.

import itertools
from operator import itemgetter
sorted_animals = sorted(animals, key=itemgetter('size'))

Then use following code to group your list of dictionary.

for key, group in itertools.groupby(sorted_animals, key=lambda x:x['size']):
    print key,
    print list(group)

After you will get following result.

large [{'name': 'cow', 'size': 'large'},

       {'name': 'pony', 'size': 'large'}]
medium [{'name': 'rabbit', 'size': 'medium'},

        {'name': 'squirrel', 'size': 'medium'},
        {'name': 'fox', 'size': 'medium'}]
small [{'name': 'bird', 'size': 'small'},

       {'name': 'fish', 'size': 'small'}]

Enjoy, Your list of dictionary is group by dictionary key values.