I have the following JSON and I need to get the plain name value using JSONPath:
{
"single" : {
"id" : 1,
"name" : "Item name"
}
}
Expression that I used is $.single.name but I always get an array:
[ "Item name" ]
instead of a string value ("Item name").
but I always get an array:
That is meant to happen. As you can read in this documentation, under 'Result' (almost at the bottom):
Please note, that the return value of jsonPath is an array, which is also a valid JSON structure. So you might want to apply jsonPath to the resulting structure again or use one of your favorite array methods as sort with it.
So basically it will always return an array. If you need the data as an other type, e.g. a String in this case, you will have to do the conversion yourself I'm afraid.
~first it will return first element of the resulting array). Hate doing things like that, but if there was no other way…
[*] to the end of your JSONPath query. It flattened the array being returned for me.
wrap property. You can read more about the implications here: npmjs.com/package/…I was using the Java implementation of JSONPath and got to the very same issue. What worked for me was to add '[0]' to the json path string. So in your case:
$.single.name[0]
data[?(@.id==9617)][0].is_favorite this doesnt work either data[?(@.id==9617)].[0].is_favorite
{state:{apiVersion:"V3_0",errorLevel:0,errorMessage:null,errorLink:null},data:[{id:94617,is_favorite:true,vip_sub_offers:[],vouchers:[{id:11613004,code:"F8JL2",offer:94617,subOffer:1613,validTo:"2016-05-20T23:59:59.000",state:"USED",stateCode:2,obtainType:"NORMAL",redirectUrl:null,phoneNumber:null,messageText:null,shopId:94614,assignTime:"2016-05-19T00:00:03.000",useTime:"2016-05-19T00:00:05.000"}]}]}
It depends of the library implementations in which some of them are rigid and others offer an option to make the developer smile.
For example in nodejs there is a npm module : https://www.npmjs.com/package/jsonpath
Which have a method called value, which does exactly what we need
jp.value(obj, pathExpression[, newValue])
Returns the value of the first element matching pathExpression. If newValue is provided, sets the value of the first matching element and returns the new value.
String json = "...";
Object document = ...parse(json);
String author0 = JsonPath.read(document, "$.store.book[0].author");
As you can see author0 is a string, not an array
In case you got this error
"Unable to get a scalar value for expression $.yourfield"
You have just to configure the EvaluateJsonPath processor by changing the return type property value to 'json' instead of 'auto-detect'
In an Azure Bicep template, value worked for me, in extracting a single parameter from a jsonc parameter file: $.parameters.aksAgentPoolIdentityPrincipalId.value
One could fathom a guess that in my case this is used as the implementation:
https://github.com/json-path/JsonPath
In javascript it is possible to get a single value addressed by a path from a json object using the npm library jsonpath-plus
Use the option { wrap: false } to avoid the array wrapper.
import { JSONPath } from 'jsonpath-plus';
const json = {
single : {
id : 1,
name : "Item name"
}
}
const path = '$.single.name'
console.log(JSONPath({json, path: path, wrap: false})) // => Item name
jsonpath returns an object of net.minidev.json.JSONArray.JSONArray from the read method. This class has size() and get(int) methods which can be used to retrieve specific values. The below example prints the 0th element as retrieved.
JSONArray o=docCtx.read("json path ...");
System.out.println(o.get(0));
