Python extract values in JSON array to form a new key-value pair
Question:
Given an array of JSON objects as:
arr=[{"id": "abc", "value": "123"}, {"id": "xyz", "value": "456"}]
I would like to output a single JSON object like:
new_arr={"abc":123,"xyz":456}
Currently I can extract the elements like arr[0]['id'] but I am wondering what’s the one-liner or better way to form the output.
Answers:
A one-liner to extract the ids and values would be like this:
new_arr = {item['id']: int(item['value']) for item in arr}
as the arr object contains the value as a str you need to convert it to an int(). The rest of the one line similar to a list comprehension with dict as the base element to add to, thereby being a dict comprehension. Though this assumes that all dicts have a id and value combination (which is unknown from your data and am assuming that they always have an id and value)
One alternative, showing the versatility of itemgetter:
from operator import itemgetter
arr = [{"id": "abc", "value": "123"}, {"id": "xyz", "value": "456"}]
# itemgetter creates a function to extract the values at id and value
pair = itemgetter("id", "value")
# use map to apply the function to each element of arr
d = dict(map(pair, arr))
# print the result
print(d)
Output
{'abc': '123', 'xyz': '456'}
One line solution can be this:
new_arr = {item['id']: int(item['value']) for item in arr}
Or you can use itemgetter opertaror:
new = dict(map(itemgetter("id", "value"), arr))
Minimum code I think
arr = [{"id": "abc", "value": "123"}, {"id": "xyz", "value": "456"}]
json = {item['id']: item['value'] for item in arr}
print(json)
result:
{'abc': '123', 'xyz': '456'}
Given an array of JSON objects as:
arr=[{"id": "abc", "value": "123"}, {"id": "xyz", "value": "456"}]
I would like to output a single JSON object like:
new_arr={"abc":123,"xyz":456}
Currently I can extract the elements like arr[0]['id'] but I am wondering what’s the one-liner or better way to form the output.
A one-liner to extract the ids and values would be like this:
new_arr = {item['id']: int(item['value']) for item in arr}
as the arr object contains the value as a str you need to convert it to an int(). The rest of the one line similar to a list comprehension with dict as the base element to add to, thereby being a dict comprehension. Though this assumes that all dicts have a id and value combination (which is unknown from your data and am assuming that they always have an id and value)
One alternative, showing the versatility of itemgetter:
from operator import itemgetter
arr = [{"id": "abc", "value": "123"}, {"id": "xyz", "value": "456"}]
# itemgetter creates a function to extract the values at id and value
pair = itemgetter("id", "value")
# use map to apply the function to each element of arr
d = dict(map(pair, arr))
# print the result
print(d)
Output
{'abc': '123', 'xyz': '456'}
One line solution can be this:
new_arr = {item['id']: int(item['value']) for item in arr}
Or you can use itemgetter opertaror:
new = dict(map(itemgetter("id", "value"), arr))
Minimum code I think
arr = [{"id": "abc", "value": "123"}, {"id": "xyz", "value": "456"}]
json = {item['id']: item['value'] for item in arr}
print(json)
result:
{'abc': '123', 'xyz': '456'}