How do I look up the 'id' associated with the a person's 'name' when the 2 are in a dictionary?
user = 'PersonA'
id = ? #How do I retrieve the 'id' from the user_stream json variable?
[
{
'name': 'PersonA',
'id': '135963'
},
{
'name': 'PersonB',
'id': '152265'
},
]
You'll have to decode the JSON structure and loop through all the dictionaries until you find a match:
for person in json.loads(user_stream):
if person['name'] == user:
id = person['id']
break
else:
# The else branch is only ever reached if no match was found
raise ValueError('No such person')
If you need to make multiple lookups, you probably want to transform this structure to a dict to ease lookups:
name_to_id = {p['name']: p['id'] for p in json.loads(user_stream)}
then look up the id directly:
id = name_to_id.get(name) # if name is not found, id will be None
The above example assumes that names are unique, if they are not, use:
from collections import defaultdict
name_to_id = defaultdict(list)
for person in json.loads(user_stream):
name_to_id[person['name']).append(person['id'])
# lookup
ids = name_to_id.get(name, []) # list of ids, defaults to empty
This is as always a trade-off, you trade memory for speed.
else block be indented on the same level as the if block?for loop. It is executed if we didn't break out of the loop.Martijn Pieters's solution is correct, but if you intend to make many such look-ups it's better to load the json and iterate over it just once, and not for every look-up.
name_id = {}
for person in json.loads(user_stream):
name = person['name']
id = person['id']
name_id[name] = id
user = 'PersonA'
print name_id[user]
persons = json.loads(...)
results = filter(lambda p:p['name'] == 'avi',persons)
if results:
id = results[0]["id"]
results can be more than 1 of course..
