sorting and grouping multiple dictionaries in python

Question

I have an unknown number of dictionaries each identified by a specific code.

All of the values are create dynamically, so the codes to group by are unknown.
I am hoping someone might be able to help me identify the best way to group the dictionaries so that I can then move through each to produce a table. There are actually about 7 items in the dictionary.

Each dictionary is a row in the table.

example:

results = ['GROUP1':{'name':'Sam', 'code':'CDZ', 'cat_name':'category1',   'cat_code':'GROUP1'}, 'GROUP1':{'name':'James', 'code':'CDF', 'cat_name':'category1',   'cat_code':'GROUP1'}, 'GROUP2':{'name':'Ellie', 'code':'CDT', 'cat_name':'category2',   'cat_code':'GROUP2'}]

I want to be able to format these dictionaries into a table using to produce the following:

GROUP1 - category1
CODE | NAME
CDZ | Sam
CDF | James

GROUP2 - category2
CODE | NAME
CDT | Ellie

Thanks so much in advance.

John La Rooy · Accepted Answer · 2013-03-04 03:44:57Z

1

If results is a list of dicts like this

>>> results = [
...     {'name': 'Sam', 'code': 'CDZ', 'cat_name': 'category1', 'cat_code': 'GROUP1'},
...     {'name': 'James', 'code': 'CDF', 'cat_name': 'category1', 'cat_code': 'GROUP1'},
...     {'name': 'Ellie', 'code': 'CDT', 'cat_name': 'category2', 'cat_code': 'GROUP2'}] 
>>> from collections import defaultdict
>>> D = defaultdict(list)
>>> for item in results:
...  D[item['cat_code'], item['cat_name']].append((item['code'], item['name']))
... 
>>> import pprint
>>> pprint.pprint(dict(D))
{('GROUP1', 'category1'): [('CDZ', 'Sam'), ('CDF', 'James')],
 ('GROUP2', 'category2'): [('CDT', 'Ellie')]}

You can iterate through D.items() and do whatever you like

answered Mar 4, 2013 at 3:44

John La Rooy

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1 Comment

devjess Over a year ago

Perfect! Thank you! I knew it had to be simpler than I was making it.

John Zwinck · Accepted Answer · 2013-03-04 03:26:56Z

0

Your first two problems are that your example input is not valid Python (the dict literal syntax is {}, not []), and you cannot have two identical keys in one dict. Until you fix these, we can't do anything. I'm not sure how you'd want to fix the duplicate keys problem--maybe you actually want an array of dicts instead of a dict of dicts?

answered Mar 4, 2013 at 3:26

John Zwinck

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1 Comment

devjess Over a year ago

Ah! Yes I think you are right actually! I might be back soon with an edit.

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