Find element in list of objects with explicit key value

Question

I have a list of objects in python:

accounts = [
    {
        'id': 1,
        'title': 'Example Account 1'
    },
    {
        'id': 2,
        'title': 'Gow to get this one?'
    },
    {
        'id': 3,
        'title': 'Example Account 3'
    },
]

I need to get object with id=2.

How can I select a proper object from this list, when I know only the value of the object attributes?

possible duplicate of [Find object in list that has attribute equal to some value (that meets any condition)](http://stackoverflow.com/questions/7125467/find-object-in-list-that-has-attribute-equal-to-some-value-that-meets-any-condi) — Emil Vikström, Aug 27 '14 at 13:17

score 33 · Answer 1 · edited Feb 12 '21 at 16:03

33

Given your data structure:

>>> [item for item in accounts if item.get('id')==2]
[{'title': 'Gow to get this one?', 'id': 2}]

If item does not exist:

>>> [item for item in accounts if item.get('id')==10]
[]

That being said, if you have opportunity to do so, you might rethink your datastucture:

accounts = {
    1: {
        'title': 'Example Account 1'
    },
    2: {
        'title': 'Gow to get this one?'
    },
    3: {
        'title': 'Example Account 3'
    }
}

You might then be able to access you data directly by indexing their id or using get() depending how you want to deal with non-existent keys.

>>> accounts[2]
{'title': 'Gow to get this one?'}

>>> accounts[10]
Traceback (most recent call last):
  File "<input>", line 1, in <module>
KeyError: 10

>>> accounts.get(2)
{'title': 'Gow to get this one?'}
>>> accounts.get(10)
# None

edited Feb 12 '21 at 16:03

Chris Maes

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answered Aug 27 '14 at 13:15

Sylvain Leroux

50,096
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might be better to use `if item.get('id') == 2` in case some dict does not contain the key – Padraic Cunningham Aug 27 '14 at 13:18
as for why the data structure, I can say that I've simply been HANDED such a structure that needs ETL work... wasn't really optional that it was a [{...},{...}] format... just had to find if a key was present in any of said objects to solve a particular need. – Joshua Eric Turcotte Oct 30 '21 at 00:28

score 6 · Answer 2 · answered Aug 10 '22 at 14:16

6

The other answers are very old. The best way is with next().

next(account for account in accounts if account['id'] == 2)

See https://stackoverflow.com/a/9868665/1812732

answered Aug 10 '22 at 14:16

John Henckel

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Agree. *Note:* One will have to either handle a `StopIteration` or pass a default value to `next(iterator, default)` – Sam Morgan May 22 '23 at 14:55

score 1 · Answer 3 · answered Aug 27 '14 at 13:17

1

This will return any element from the list that has an id == 2

limited_list = [element for element in accounts if element['id'] == 2]
>>> limited_list
[{'id': 2, 'title': 'Gow to get this one?'}]

answered Aug 27 '14 at 13:17

bpgergo

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score 0 · Answer 4 · answered Aug 27 '14 at 13:19

It seems to be a weird data structure, but it can be done:

acc = [account for account in accounts if account['id'] == 2][0]

Maybe a dictionary with the id-number as key is more appropriate, as this makes the accessing easier:

account_dict = {account['id']: account for account in accounts}

Find element in list of objects with explicit key value

4 Answers4