CODEWITHSUNDEEP
pythonlistdictionary
jcloud
jcloud

Reputation: 75

How to turn a list into a nested dictionary?

Beginner programmer here. I have 2 questions.

  1. Turn a list into a nested dictionary:

    house_prices = ['£200k', '£300k', '£500k'`]

I want to turn it into--

House_price_dict = {
'house1': {'price':'£200k'},
'house2': {'price':'£300k'},
'house3': {'price:'£500k'},
}

  1. Turn two lists into a nested dictionary:

    house_prices = ['£200k', '£300k', '£500k'`]

    no_of_bedrooms = [2, 3, 5]

I want to turn into--

house_info_dict = {
    'house1': {
        'price':'£200k',
        'no_of_bedrooms':2,
        },
    'house2': {
        'price':'£300k',
        'no_of_bedrooms': 3,
        },
    'house3': {
        'price:'£500k',
        'no_of_bedrooms': 5,
        },
    }

Upvotes: 2

Views: 101

Answers (3)

SpiderPig1297
SpiderPig1297

Reputation: 325

d = {} 
for i in xrange(len(house_prices)):
    d["house{}".format(i+1)] = { "price": house_prices[i] }

For the second part:

d = {} 
for i in xrange(len(house_prices)):
    d["house{}".format(i+1)] = { "price": house_prices[i], 'no_of_bedrooms': no_of_bedrooms[i] }

Note that house_prices and no_of_bedrooms must be in the same size, otherwise IndexError will be raised.

Upvotes: 2

Alok
Alok

Reputation: 10544

We can use dictionany comprehension

house_prices = ['£200k', '£300k', '£500k']
House_price_dict = {f'house{idx}':{'price':i} for idx, i in enumerate(house_prices, start=1)}

#{'house1': {'price': '£200k'},
# 'house2': {'price': '£300k'},
# 'house3': {'price': '£500k'}}

no_of_bedrooms = [2, 3, 5]
house_info_dict = {f'house{idx}':{'price':i[0], 'no_of_bedrooms': i[1]} for idx, i in enumerate(zip(house_prices, no_of_bedrooms), start=1)}

#{'house1': {'price': '£200k', 'no_of_bedrooms': 2},
# 'house2': {'price': '£300k', 'no_of_bedrooms': 3},
# 'house3': {'price': '£500k', 'no_of_bedrooms': 5}}

Upvotes: 0

thebjorn
thebjorn

Reputation: 27311

The zip function takes multiple lists and returns tuples with one element from each list:

>>> house_prices = ['200k', '300k', '500k']
>>> no_of_bedrooms = [2, 3, 5]
>>>
>>> list(zip(house_prices, no_of_bedrooms))
[('200k', 2), ('300k', 3), ('500k', 5)]
>>>

zip returns a generator, so I convert it to list above to see the result.

There is a built-in enumerate function that returns both the index and the value in a list:

>>> for i, n in enumerate(['a', 'b', 'c'], start=1):
...     print(i, n)
...
1 a
2 b
3 c
>>>

combining the two, gives:

>>> list(enumerate(zip(house_prices, no_of_bedrooms), start=1))
[(1, ('200k', 2)), (2, ('300k', 3)), (3, ('500k', 5))]

and you can feed this into a dict comprehension:

>>> house_info_dict = {'house%d' % i: {
...     'price': p,
...     'no_of_bedrooms': n
... } for i, (p, n) in enumerate(zip(house_prices, no_of_bedrooms), start=1)}
>>> house_info_dict
{'house3': {'no_of_bedrooms': 5, 'price': '500k'}, 'house2': {'no_of_bedrooms': 3, 'price': '300k'}, 'house1': {'no_of_bedrooms': 2, 'price': '200k'}}

a trick to print it in a prettier format is to use the json module:

>>> import json
>>> print(json.dumps(house_info_dict, indent=4))
{
    "house3": {
        "no_of_bedrooms": 5,
        "price": "500k"
    },
    "house2": {
        "no_of_bedrooms": 3,
        "price": "300k"
    },
    "house1": {
        "no_of_bedrooms": 2,
        "price": "200k"
    }
}
>>>

Upvotes: 3

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