[json] How to filter by string in JSONPath?

I have a JSON response from the Facebook API that looks like this:

{
  "data": [
     {
       "name": "Barack Obama", 
       "category": "Politician", 
       "id": "6815841748"
     }, 
     {
       "name": "Barack Obama's Dead Fly", 
       "category": "Public figure", 
       "id": "92943557739"
     }]
 }

I want to apply JSONPath to it to only return results with a category of "Politician". From what I've read, it appears that I need to do:

$.data[?(@.category=='Politician')]

but according to the testing tool I found, this doesn't work. I found another question which suggests that I should use "eq" instead of "==", but that doesn't work either. What am I getting wrong here?

''Alastair, you can use this lib and tool; DefiantJS. It enables XPath queries on JSON structures and you can test and validate this XPath:

//data[category="Politician"]

DefiantJS extends the global object with the method "search", which in turn returns an array with the matches. In Javascript, it'll look like this:

var person = JSON.search(json_data, "//people[category='Politician']");
console.log( person[0].name );
// Barack Obama

Drop the quotes:

List<Object> bugs = JsonPath.read(githubIssues, "$..labels[?(@.name==bug)]");

See also this Json Path Example page

The browser testing tools while convenient can be a bit deceiving. Consider:

{
  "resourceType": "Encounter",
  "id": "EMR56788",
  "text": {
    "status": "generated",
    "div": "Patient admitted with chest pains</div>"
  },
  "status": "in-progress",
  "class": "inpatient",
  "patient": {
    "reference": "Patient/P12345",
    "display": "Roy Batty"
  }
}

Most tools returned this as false:

$[?(@.class==inpatient)]

But when I executed against

<dependency>
    <groupId>com.jayway.jsonpath</groupId>
    <artifactId>json-path</artifactId>
    <version>1.2.0</version>
</dependency>

It returned true. I recommend writing a simple unit test to verify rather than rely on the browser testing tools.

I didn't find find the correct jsonpath filter syntax to extract a value from a name-value pair in json.

Here's the syntax and an abbreviated sample twitter document below.

This site was useful for testing:

The jsonpath filter expression:

.events[0].attributes[?(@.name=='screen_name')].value

Test document:

{
  "title" : "test twitter",
  "priority" : 5,
  "events" : [ {
    "eventId" : "150d3939-1bc4-4bcb-8f88-6153053a2c3e",
    "eventDate" : "2015-03-27T09:07:48-0500",
    "publisher" : "twitter",
    "type" : "tweet",
    "attributes" : [ {
      "name" : "filter_level",
      "value" : "low"
    }, {
      "name" : "screen_name",
      "value" : "_ziadin"
    }, {
      "name" : "followers_count",
      "value" : "406"
    } ]
  } ]
}