Find string within JSON with Python

Question

I'm currently getting a very long JSON and I'm trying to pick out 2 pieces of information from it through Python 2.7.

The JSON looks roughly like this:

{
  'device': [
    {
      'serial': '00000000762c1d3c',
      'registered_id': '019'
    },
    {
      'serial': '000000003ad192f2',
      'registered_id': '045'
    },
    {
      'serial': '000000004c9898aa',
      'registered_id': '027'
    }
  ],
}

Within this JSON I'm looking for a specific serial that might match with one in the JSON. If it does, it should print out the registered_id as well.

I've tried using a simple script, even without the registered_id but I'm getting nowhere.:

if '00000000762c1d3c' not in data['device']:
        print 'not there'
else:
        print 'there'

Thanks for your suggestions!

Solution 1

date['device'] contains a list of objects, so you should treat it as such and iterate over them:

for element in data['device']:
    if element['serial'] == '00000000762c1d3c':
        print 'there'
        print element['registered_id']
        break
else:
    print 'not there'

This is using the somehow lesser-known for-else construct: https://docs.python.org/3/tutorial/controlflow.html#break-and-continue-statements-and-else-clauses-on-loops

Solution 2

first, your input isn't json. Json uses double quotes. But suppose you successfully loaded it with json, it's now a dictionary, called d.

Then you can scan all sub-dicts of d and test serial key against your value, stopping when found using any and a generator comprehension:

print(any(sd['serial']=='00000000762c1d3c' for sd in d['device']))

returns True if serial found False otherwise.