Python: Find location of data within JSON object, parse the corresponding data

I am getting this JSON object from a Simplegeo request. For certain areas, you will not have Address data. In those cases, I want to be able to find the part in the data with "subcategory":"County" and then query the corresponding name.

What is the best way to find the location of data within a JSON response and grab the correesponding data?

{
    "query": {
        "latitude": 34.078195,
        "longitude": -118.185497,
        "address": "90032",
        "confidence": 0.714,
        "precision": "zip"
    },
    "timestamp": 1313717557.449,
    "features": [
        {
            "handle": "SG_13ChTM4q9Qo0OoZI5q453G_34.078617_-118.185973",
            "href": "http://api.simplegeo.com/1.0/features/SG_13ChTM4q9Qo0OoZI5q453G_34.078617_-118.185973.json",
            "abbr": null,
            "attribution": "(c) OpenStreetMap (http://openstreetmap.org/) and contributors",
            "classifiers": [
                {
                    "category": "Commercial Area",
                    "type": "Public Place",
                    "subcategory": null
                }
            ],
            "name": "KMPC-AM",
            "license": "http://creativecommons.org/licenses/by-sa/2.0/",
            "bounds": [
                -118.187194,
                34.076831,
                -118.184752,
                34.080421
            ]
        },
        {
            "handle": "SG_5zlubcQBdPWX5zY02QtxeT_34.080185_-118.184829",
            "name": "06037201401",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.193786,
                34.075513,
                -118.178021,
                34.086444
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_5zlubcQBdPWX5zY02QtxeT_34.080185_-118.184829.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "US Census",
                    "type": "Region",
                    "subcategory": "Tract"
                }
            ]
        },
        {
            "handle": "SG_01i8SelQjR6LBuBBGei63D_34.081001_-118.177407",
            "name": "El Sereno",
            "license": "Not For Redistribution",
            "bounds": [
                -118.19758,
                34.061731,
                -118.155504,
                34.105109
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_01i8SelQjR6LBuBBGei63D_34.081001_-118.177407.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Neighborhood",
                    "type": "Region",
                    "subcategory": null
                }
            ]
        },
        {
            "handle": "SG_0Zvp5oQfiIlufuV5WlR0Bs_34.079519_-118.177738",
            "name": "90032",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.202841,
                34.060453,
                -118.155292,
                34.101921
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_0Zvp5oQfiIlufuV5WlR0Bs_34.079519_-118.177738.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Postal Code",
                    "type": "Region",
                    "subcategory": null
                }
            ]
        },
        {
            "handle": "SG_2EAf2lwKihpnQQbH5qQBow_34.085193_-118.233164",
            "name": "Assembly District 45",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.344812,
                34.040466,
                -118.155292,
                34.126937
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_2EAf2lwKihpnQQbH5qQBow_34.085193_-118.233164.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Legislative District",
                    "type": "Region",
                    "subcategory": "Provincial (Lower)"
                }
            ]
        },
        {
            "handle": "SG_0iiFtWc7rXBJ6VYl2kuO0L_34.085508_-117.985139",
            "name": "Congressional District 32",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.196746,
                34.001855,
                -117.840549,
                34.194325
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_0iiFtWc7rXBJ6VYl2kuO0L_34.085508_-117.985139.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Legislative District",
                    "type": "Region",
                    "subcategory": "National"
                }
            ]
        },
        {
            "handle": "SG_7NZeInBzM4Mv73P62VZzjl_34.074117_-117.991920",
            "name": "State Senate District 24",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.215856,
                33.986182,
                -117.840549,
                34.194731
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_7NZeInBzM4Mv73P62VZzjl_34.074117_-117.991920.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Legislative District",
                    "type": "Region",
                    "subcategory": "Provincial (Upper)"
                }
            ]
        },
        {
            "handle": "SG_63gaN6Xi7zAjBxeFk74UBz_34.106997_-118.411704",
            "name": "Los Angeles",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.668176,
                33.703652,
                -118.155289,
                34.337306
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_63gaN6Xi7zAjBxeFk74UBz_34.106997_-118.411704.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Municipal",
                    "type": "Region",
                    "subcategory": "City"
                }
            ]
        },
        {
            "handle": "SG_5lHwuPKvcJYpKhy8MR1ZMZ_34.100887_-118.390729",
            "name": "Los Angeles Unified School District",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.668058,
                33.659547,
                -118.142667,
                34.353672
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_5lHwuPKvcJYpKhy8MR1ZMZ_34.100887_-118.390729.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "School District",
                    "type": "Region",
                    "subcategory": "Unified"
                }
            ]
        },
        {
            "handle": "SG_6RRdLsqpHXF3Yu1EXCPORn_33.971007_-117.971917",
            "name": "Los Angeles",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.991667,
                33.391667,
                -117.008333,
                34.333333
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_6RRdLsqpHXF3Yu1EXCPORn_33.971007_-117.971917.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Urban Area",
                    "type": "Region",
                    "subcategory": null
                }
            ]
        },
        {
            "handle": "SG_6Em6St6NgZtuvorHtngjTU_34.197952_-118.261063",
            "name": "Los Angeles",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -118.951721,
                32.75004,
                -117.645604,
                34.823193
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_6Em6St6NgZtuvorHtngjTU_34.197952_-118.261063.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Administrative",
                    "type": "Region",
                    "subcategory": "County"
                }
            ]
        },
        {
            "handle": "SG_2MySaPILVQG3MoXrsVehyR_37.215297_-119.663837",
            "name": "California",开发者_StackOverflow社区
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -124.482003,
                32.528832,
                -114.131211,
                42.009517
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_2MySaPILVQG3MoXrsVehyR_37.215297_-119.663837.json",
            "abbr": "CA",
            "classifiers": [
                {
                    "category": "Subnational",
                    "type": "Region",
                    "subcategory": "State"
                }
            ]
        },
        {
            "handle": "SG_3tLT0I5cOUWIpoVOBeScOx_41.316130_-119.116571",
            "name": "America/Los_Angeles",
            "license": "creativecommons.org/publicdomain/zero/1.0/",
            "bounds": [
                -124.733253,
                32.534622,
                -114.039345,
                49.002892
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_3tLT0I5cOUWIpoVOBeScOx_41.316130_-119.116571.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "Time Zone",
                    "type": "Region",
                    "subcategory": null
                }
            ]
        },
        {
            "handle": "SG_3uwSAEdXVBzK1ZER9Nqkdp_45.687160_-112.493107",
            "name": "United States of America",
            "license": "http://creativecommons.org/publicdomain/mark/1.0/",
            "bounds": [
                -179.142471,
                18.930138,
                179.78115,
                71.41218
            ],
            "href": "http://api.simplegeo.com/1.0/features/SG_3uwSAEdXVBzK1ZER9Nqkdp_45.687160_-112.493107.json",
            "abbr": null,
            "classifiers": [
                {
                    "category": "National",
                    "type": "Region",
                    "subcategory": null
                }
            ]
        }
    ],
    "weather": {
        "wind_speed": "0 meters per second",
        "temperature": "84F",
        "dewpoint": "57F",
        "cloud_cover": "0%",
        "wind_direction": "0 degrees",
        "forecast": {
            "tonight": {
                "conditions": "Fog",
                "precipitation": "0%",
                "temperature": {
                    "max": "70F",
                    "min": "66F"
                }
            },
            "tomorrow": {
                "conditions": "Clear",
                "precipitation": "0%",
                "temperature": {
                    "max": "89F",
                    "min": "68F"
                }
            },
            "today": {
                "conditions": "Mostly clear",
                "precipitation": "0%",
                "temperature": {
                    "max": "94F",
                    "min": "71F"
                }
            }
        },
        "conditions": "Clear"
    },
    "demographics": {
        "population_density": 5808,
        "acs": {
            "error": "You must supply ACS table IDs with demographics.acs__table=<table_id_1>&demographics.acs__table=<table_id_2>... parameters."
        }
    },
    "intersections": [
        {
            "distance": 277.0035787874508,
            "geometry": {
                "type": "Point",
                "coordinates": [
                    -118.1874986,
                    34.0800544
                ]
            },
            "properties": {
                "highways": [
                    {
                        "osm_way_id": "13375722",
                        "type": "residential",
                        "name": "Bowman Boulevard"
                    },
                    {
                        "osm_way_id": "13435504",
                        "type": "residential",
                        "name": "Verdemour Avenue"
                    }
                ],
                "attribution": "(c) OpenStreetMap (http://openstreetmap.org/) and contributors",
                "license": "http://creativecommons.org/licenses/by-sa/2.0/"
            },
            "type": "Feature",
            "id": "123133103"
        },
        {
            "distance": 278.5007862228104,
            "geometry": {
                "type": "Point",
                "coordinates": [
                    -118.187905,
                    34.07971
                ]
            },
            "properties": {
                "highways": [
                    {
                        "osm_way_id": "13375722",
                        "type": "residential",
                        "name": "Bowman Boulevard"
                    },
                    {
                        "osm_way_id": "13286592",
                        "type": "residential",
                        "name": "Lynnfield Street"
                    },
                    {
                        "osm_way_id": "13435505",
                        "type": "residential",
                        "name": "Verdemour Avenue"
                    }
                ],
                "attribution": "(c) OpenStreetMap (http://openstreetmap.org/) and contributors",
                "license": "http://creativecommons.org/licenses/by-sa/2.0/"
            },
            "type": "Feature",
            "id": "122609716"
        },
        {
            "distance": 295.66530721862495,
            "geometry": {
                "type": "Point",
                "coordinates": [
                    -118.1870694,
                    34.0805132
                ]
            },
            "properties": {
                "highways": [
                    {
                        "osm_way_id": "13375722",
                        "type": "residential",
                        "name": "Bowman Boulevard"
                    },
                    {
                        "osm_way_id": "13468782",
                        "type": "residential",
                        "name": "Carter Drive"
                    }
                ],
                "attribution": "(c) OpenStreetMap (http://openstreetmap.org/) and contributors",
                "license": "http://creativecommons.org/licenses/by-sa/2.0/"
            },
            "type": "Feature",
            "id": "123133105"
        },
        {
            "distance": 308.18108469988266,
            "geometry": {
                "type": "Point",
                "coordinates": [
                    -118.1830009,
                    34.0763492
                ]
            },
            "properties": {
                "highways": [
                    {
                        "osm_way_id": "13441050",
                        "type": "residential",
                        "name": "Richelieu Avenue"
                    },
                    {
                        "osm_way_id": "13470172",
                        "type": "residential",
                        "name": "Richelieu Terrace"
                    }
                ],
                "attribution": "(c) OpenStreetMap (http://openstreetmap.org/) and contributors",
                "license": "http://creativecommons.org/licenses/by-sa/2.0/"
            },
            "type": "Feature",
            "id": "123621465"
        },
        {
            "distance": 318.5882396290064,
            "geometry": {
                "type": "Point",
                "coordinates": [
                    -118.1840727,
                    34.080806
                ]
            },
            "properties": {
                "highways": [
                    {
                        "osm_way_id": "13313919",
                        "type": "residential",
                        "name": "Bedilion Street"
                    },
                    {
                        "osm_way_id": "13468783",
                        "type": "residential",
                        "name": "Carter Drive"
                    }
                ],
                "attribution": "(c) OpenStreetMap (http://openstreetmap.org/) and contributors",
                "license": "http://creativecommons.org/licenses/by-sa/2.0/"
            },
            "type": "Feature",
            "id": "122784176"
        }
    ],
    "address": {
        "geometry": {
            "coordinates": [
                -118.184913,
                34.076448
            ],
            "type": "Point"
        },
        "properties": {
            "address": "4501 Richelieu Ter",
            "distance": "0.2",
            "postcode": "90032",
            "city": "Los Angeles",
            "county": "Los Angeles",
            "province": "CA",
            "country": "US"
        },
        "type": "Feature"
    }
}

First you will need to convert your JSON string into a Python dictionary using the json module.

If data is your new dictionary, the information you are looking for is in the list data["features"]. You will need to iterate over this list and filter out any entries that you do not want. In your case, for each item in data["features"], you only want entries where item["classifiers"][0]["subcategory"] == "County".

You can do all of this in a list comprehension, for example:

import json

data = json.loads(json_string)
counties = [item for item in data["features"] 
            if item["classifiers"][0]["subcategory"] == "County"]

This would give you the full dictionary for each county, if you are only interested in the "name" field you can use this:

counties = [item["name"] for item in data["features"]
            if item["classifiers"][0]["subcategory"] ==  "County"]

The JSON object you provided seemed to have a very consistent format, but if that is not always the case you may need to do some additional checking to make sure the dictionary keys are present.