Find the minimum of a list of dictionaries with respect to a specific key

Question

I have this :

[{'prisonniers': [], 'sécurité': '47'},{'prisonniers': [],'sécurité':'92'}, {'prisonniers': [], 'sécurité': '38'}]

And I need to put inside another list the dict which has the lowest 'sécurity', in this case, I need this:

myList = [{'prisonniers': [], 'sécurité': '38'}]

Create a function to extract the security value (as number) from one list item and use it as `key` for `min` function over the list. — Michael Butscher, Dec 08 '18 at 13:40
I'm certain this must be a duplicate, but I can't find a good dupe target right now. In any case, there are dozens of existing questions on Stack Overflow about manipulating a list of dicts, and about techniques like using the `key` argument of `min`, `max`, and `sorted`. — Daniel Pryden, Dec 08 '18 at 13:50
For example, there's this highly upvoted question, which covers very similar ground: [How do I sort a list of dictionaries by a value of the dictionary?](https://stackoverflow.com/questions/72899/how-do-i-sort-a-list-of-dictionaries-by-a-value-of-the-dictionary) — Daniel Pryden, Dec 08 '18 at 13:54

score 4 · Answer 1 · answered Dec 08 '18 at 13:40

min function accepts an argument named key, it will find the minimum of an iterable based on key that can be callable. so, try this:

l = [{'prisonniers': [], 'sécurité': '47'},{'prisonniers': [],'sécurité':'92'}, {'prisonniers': [], 'sécurité': '38'}]

min(l, key=lambda x:x['sécurité'])

the output will be

{'prisonniers': [], 'sécurité': '38'}

score 3 · Answer 2 · answered Dec 08 '18 at 14:00

Similar to mehrdad-pedramfar's answer, but I prefer using itemgetter from the operator module for readability.

Setup:

from operator import itemgetter
data = [{'prisonniers': [], 'sécurité': '47'},{'prisonniers': [],'sécurité':'92'}, {'prisonniers': [], 'sécurité': '38'}]

Solution:

>>> min(data, key=itemgetter('sécurité'))
{'prisonniers': [], 'sécurité': '38'}

score 1 · Answer 3 · edited Dec 09 '18 at 07:00

1

You can use min to do that, setting as key securite for finding the minimum value:

inList = [{'prisonniers': [], 'securite': '47'},{'prisonniers': [],'securite':'92'}, {'prisonniers': [], 'securite': '38'}]

value = min(inList, key=lambda elem: elem['securite'])
print(value)

Output:

{'prisonniers': [], 'securite': '38'}

In the above example, I replaced é with e but it will work fine in your case too.

edited Dec 09 '18 at 07:00

Mehrdad Pedramfar

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answered Dec 08 '18 at 13:42

Vasilis G.

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@mehrdad-pedramfar sorry, obviously you got it first and me a couple of seconds later. – Vasilis G. Dec 08 '18 at 13:44
@mehrdad-pedramfar: Just because someone else posted an equivalent answer doesn't mean the answer deserves a downvote. We don't want to upvote the "fastest gun in the West" but rather the *best* answer. – Daniel Pryden Dec 08 '18 at 13:46
@Daniel Pryden, thank you for your remark. It just took a little longer to post it than mehrdad-pedramfar. – Vasilis G. Dec 08 '18 at 13:49
@FatihAkman should I find a different name for that variable then? – Vasilis G. Dec 08 '18 at 13:50
Thank's but i have a problem. I have a dictionnary like this one – Fatih Akman Dec 08 '18 at 13:50
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@FatihAkman: If you need to clarify your question, edit your question rather than adding more comments. – Daniel Pryden Dec 08 '18 at 13:52

score 0 · Answer 4 · answered Dec 08 '18 at 13:51

You can use below code: Step: Find the least "sécurité" using min([ i['sécurité'] for i in input_list]) then use list comprehension again print the matching "sécurité" with minimum value:

aa = [print(i) for j in input_list if j['sécurité'] == min([ i['sécurité'] for i in input_list])]

Find the minimum of a list of dictionaries with respect to a specific key

4 Answers4