Python dictionary list merging

Question

I want to join the dictionaries in a list whose key 'user' are the same, but I don't realize how. for example:

[{'count2': 34, 'user': 2},
 {'count4': 233, 'user': 2},
 {'count2': 234, 'user': 4},
 {'count4': 344, 'user': 5}]

would become:

[{'count2': 34, 'count4': 233, 'user': 2 },
 {'count2': 234, 'user': 4},
 {'count4': 344, 'user': 5}]

I searched extensively without found something similar in stack overflow, any help would be greatly appreciated.

Answer 1

from collections import defaultdict

dl = [{'count2': 34, 'user': 2},
{'count4': 233, 'user': 2},
{'count2': 234, 'user': 4},
{'count4': 344, 'user': 5}]
print dl

dd = defaultdict(dict)
for d in dl:
    dd[d['user']].update(d)
print dd.values()