Merging dictionaries and keeping unique values

Question

I am trying to merge a list of dictionaries in order to get a particular result.

This my list of dictionaries:

data = [{'city': 'San Francisco', 'state': 'CA', 'id': 1, 'name': 'The Musical Hop'}, 
        {'city': 'New York', 'state': 'NY', 'id': 2, 'name': 'The Dueling Pianos Bar'}, 
        {'city': 'San Francisco', 'state': 'CA', 'id': 3, 'name': 'Park Square Live Music & Coffee'}]

This is the desired outcome:

[{
    "city": "San Francisco",
    "state": "CA",
    "venues": [{
      "id": 1,
      "name": "The Musical Hop",
    }, {
      "id": 3,
      "name": "Park Square Live Music & Coffee",
    }]
  }, {
    "city": "New York",
    "state": "NY",
    "venues": [{
      "id": 2,
      "name": "The Dueling Pianos Bar",
    }]
  }]

I tried this:

import operator
import itertools
outputList = []
for i,g in itertools.groupby(d,key= operator.itemgetter("city")):
    outputList.append(list(g))

Answer 1

Don't forget to sort your data before applying groupby:

import itertools
import operator

result = []

for (city, state), group in itertools.groupby(
        sorted(data, key=operator.itemgetter('city')),
        key=operator.itemgetter('city', 'state')
):
    venues = [{'id': obj['id'], 'name': obj['name']} for obj in group]
    result.append(dict(
        city=city,
        state=state,
        venues=venues
    ))

print(result)

Output:

[{'city': 'New York',
  'state': 'NY',
  'venues': [{'id': 2, 'name': 'The Dueling Pianos Bar'}]},
 {'city': 'San Francisco',
  'state': 'CA',
  'venues': [
      {'id': 1, 'name': 'The Musical Hop'},
      {'id': 3, 'name': 'Park Square Live Music & Coffee'}]
  }]