extract dicts from list of dict based on key value pair in dict

Question

I have list of dict where i want to extract specific dicts if they contain certain key-value pairs Ex of list of dict

[
{'value': 'def', 'key': 'abc'},
{'value': 'xyz', 'key': 'mnp'},
{'value': '456', 'key': '123'},
{'value': '234', 'key': '789'}
]

I want to extract dicts where key=abc or key=mnp, like that i can add multiple condition for key

What should i do here?

I tried to modify this solution but for that i have to do multiple next, each for one condition like key=abc, key=mnp

I can't change the list or how it's formatted because it is response of web request

you mean `or`, not `and` right! ;-) [ where key=abc and key=mnp] — JGFMK, Dec 26 '19 at 18:23

score 2 · Answer 1 · answered Dec 26 '19 at 18:33

2

#!/usr/bin/python3
d = [
{'value': 'def', 'key': 'abc'},
{'value': 'xyz', 'key': 'mnp'},
{'value': '456', 'key': '123'},
{'value': '234', 'key': '789'}
]
d = list(filter(lambda x: x['key'] in ['abc','mnp'], d))
print(d)

See it in action here

answered Dec 26 '19 at 18:33

JGFMK

8,425
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score 1 · Answer 2 · answered Dec 26 '19 at 18:35

using generator provided in the question, you make this this a two step part, where you pass your matches into a list then iterate over them using the geneartor

matches = ['abc','mbp']
for match in matches:

    print(next((item for item in d if item["key"] == match), None))
    out:
    {'value': 'xyz', 'key': 'mnp'}
    {'value': 'def', 'key': 'abc'}

score 0 · Answer 3 · answered Dec 26 '19 at 18:17

0

Unpack the list, you should edit this.

all_keys = set().union(*(d.keys() for d in mylist))

answered Dec 26 '19 at 18:17

nakE

362
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`I want to extract dicts where key=abc and key=mnp` ...I'm not sure how this helps. – decorator-factory Dec 26 '19 at 18:19
@int6h This is an example, he should edit this like I said. – nakE Dec 26 '19 at 18:21
@int6h @nakE i updated question with ```key=abc``` or ```key=mnp``` – mihir6692 Dec 26 '19 at 18:27

decorator-factory · Answer 4 · 2019-12-26T18:24:02.237

You can do this:

filtered_entries = [entry for entry in list_of_dicts if entry['key'] in ('abc', 'def', 'ghi', 'hello', 'world')]

Or this:

filtered_entries = filter(lambda entry: entry['key'] in ('abc', 'def', 'ghi', 'hello', 'world'), list_of_dicts)

Or more generally:

def extract_kv_pairs(list_of_dicts, key_condition):
    return [kv for kv in list_of_dicts if key_condition(entry['key'])]

filtered_entries = extract_kv_pairs(list_of_dicts, lambda k: k in ('abc', 'def', 'ghi', 'hello', 'world'))

# Or, if you don't like lambdas:
filtered_entries = extract_kv_pairs(list_of_dicts, ('abc', 'def', 'ghi', 'hello', 'world').__contains__)

# You can use more complicated conditions and put them in named functions:
def condition(key):
    return (len(key)%2 == 0 and 'z' not in key)
filtered_entries = extract_kv_pairs(list_of_dicts, condition)

score 0 · Answer 5 · answered Dec 26 '19 at 18:37

You could transform that list into a dictionary and query your data from it like:

 def check_list():
      list_of_dicts = [{'value': 'def', 'key': 'abc'},
                       {'value': 'xyz', 'key': 'mnp'},
                       {'value': '456', 'key': '123'},
                       {'value': '234', 'key': '789'}
                      ]
      new_dict = {d['key']: d['value'] for d in list_of_dicts}
      abc = d['abc'] if 'abc' in new_dict.keys() else None
      mnp = d['mnp'] if 'mnp' in new_dict.keys() else None

      return abc, mnp

Note that you can implement a different logic for querying or just use a for loop to search it.

Why are you assuming that `key`s will be unique? – decorator-factory Dec 26 '19 at 18:38 — decorator-factory, Dec 26 '19 at 18:38

extract dicts from list of dict based on key value pair in dict

5 Answers5