CODEWITHSUNDEEP
pythonpython-3.x
Sathish
Sathish

Reputation: 133

Difficulty getting the item count for the combinations of list of items from python dictionary

I have below input list of dictionaries

inpdata =   {"cat": [{"categories": [{"cid": 27}, {"cid": 66}, {"cid": 29}], "id": 20}, 
                     {"categories": [{"cid": 66}], "id": 21}, 
                     {"categories": [{"cid": 66}, {"cid": 27}], "id": 22}, 
                     {"categories": [{"cid": 66}, {"cid": 27}], "id": 23}, 
                     {"categories": [{"cid": 66}, {"cid": 29}, {"cid": 27}], "id": 24}]};

Am trying to get the count of id's for each cid along with the id values, I used below code for that -

allcategories = set( sec['cid'] for record in inpdata['cat'] for sec in record['categories'] )
summarize = lambda record: record['id']   
fs_cat = [
        {
            'cat':cid,
            'count':len(matches),
            'ids':[ summarize( match ) for match in matches ]
        }
        for cid in allcategories
        for matches in [[
            record for record in inpdata['cat'] if cid in [ sec['cid'] for sec in record['categories'] ]
        ]]
    ]
print(fs_cat)

This gives the output as -

[{'cat': 66, 'count': 5, 'ids': [20, 21, 22, 23, 24]},
 {'cat': 27, 'count': 4, 'ids': [20, 22, 23, 24]},
 {'cat': 29, 'count': 2, 'ids': [20, 24]}
 ]

But how can I get the combination of the categories {66,27,29} ?

I tried using below approach for getting the combinations of this input - it gives the combination of items from the list 

allcategories = {66,27,29}
for subset in itertools.chain.from_iterable(itertools.combinations(allcategories, n) for n in range(len(allcategories) + 1)):
    print(subset)

But I couldn't figure out how can I use this approach to get me the result as below for categories {66,27,29} from the 'inpdata'

result=[{'cat': '66', 'count': 5, 'ids': [20, 21, 22, 23, 24]},
        {'cat': '27', 'count': 4, 'ids': [20, 22, 23, 24]},
        {'cat': '29', 'count': 2, 'ids': [20, 24]},
        {'cat': '66&27', 'count': 4, 'ids': [20, 22, 23, 24]},
        {'cat': '66&29', 'count': 2, 'ids': [20, 24]},
        {'cat': '27&29', 'count': 2, 'ids': [20, 24]},
        {'cat': '66&27&29', 'count': 2, 'ids': [20, 24]}
        ]

Could you please suggest on how I can achieve this?

Upvotes: 4

Views: 100

Answers (1)

falsetru
falsetru

Reputation: 369224

itertools.combinations(1), itertools.combinations(2), ... upto itertools.combinations(n) will give you all combinations of fs_cat (where, n = len(fs_cat))

import itertools
import operator
from functools import reduce

fs_cat = [
    {'cat': 66, 'count': 5, 'ids': [20, 21, 22, 23, 24]},
    {'cat': 27, 'count': 4, 'ids': [20, 22, 23, 24]},
    {'cat': 29, 'count': 2, 'ids': [20, 24]},
]

result = []
for n in range(1, len(fs_cat) + 1):  # 1, 2, ..., len(fs_cat)
    for xs in itertools.combinations(fs_cat, n):
        cat = '&'.join(map(str, sorted(x['cat'] for x in xs)))
        ids = sorted(reduce(operator.and_, (set(x['ids']) for x in xs)))
        result.append({'cat': cat, 'count': len(ids), 'ids': ids})

>>> result
[{'cat': '66', 'count': 5, 'ids': [20, 21, 22, 23, 24]},
 {'cat': '27', 'count': 4, 'ids': [20, 22, 23, 24]},
 {'cat': '29', 'count': 2, 'ids': [20, 24]},
 {'cat': '27&66', 'count': 4, 'ids': [20, 22, 23, 24]},
 {'cat': '29&66', 'count': 2, 'ids': [20, 24]},
 {'cat': '27&29', 'count': 2, 'ids': [20, 24]},
 {'cat': '27&29&66', 'count': 2, 'ids': [20, 24]}]

Upvotes: 2

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