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JSON parsing with QtJson...

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  • Christian EhrlicherC Offline
    Christian EhrlicherC Offline
    Christian Ehrlicher
    Lifetime Qt Champion
    wrote on last edited by
    #7

    Because it's inside an array:

    [ ... ]

    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
    Visit the Qt Academy at https://academy.qt.io/catalog

    F 1 Reply Last reply
    1
    • Christian EhrlicherC Christian Ehrlicher

      Because it's inside an array:

      [ ... ]

      F Offline
      F Offline
      filipdns
      wrote on last edited by filipdns
      #8

      @Christian-Ehrlicher thanks, then, what I have to do to extract the data what I need?...

      1 Reply Last reply
      0
      • Christian EhrlicherC Offline
        Christian EhrlicherC Offline
        Christian Ehrlicher
        Lifetime Qt Champion
        wrote on last edited by
        #9

        @filipdns said in JSON parsing with QtJson...:

        what I have to do to extract the data what I need?...

        Extract the array I would guess... http://doc.qt.io/qt-5/qjsonarray.html

        Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
        Visit the Qt Academy at https://academy.qt.io/catalog

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        1
        • Christian EhrlicherC Christian Ehrlicher

          @filipdns said in JSON parsing with QtJson...:

          what I have to do to extract the data what I need?...

          Extract the array I would guess... http://doc.qt.io/qt-5/qjsonarray.html

          F Offline
          F Offline
          filipdns
          wrote on last edited by
          #10

          @Christian-Ehrlicher I try to work with it like array:

          var obj =JSON.parse(res)
          console.log(obj.aircraft[0].geography)

          but the return message is [object Object]...

          kshegunovK 1 Reply Last reply
          0
          • Christian EhrlicherC Offline
            Christian EhrlicherC Offline
            Christian Ehrlicher
            Lifetime Qt Champion
            wrote on last edited by Christian Ehrlicher
            #11

            Sorry but I don't understand python that much to help you.

            Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
            Visit the Qt Academy at https://academy.qt.io/catalog

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            • mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by
              #12

              Hi

              {
                "aircraft":[
                  {
                    "geography":{
                      "latitude":42.6581,
                      "longitude":5.51009,
                      "altitude":11585.4,
                      "direction":16
                    },
                    "speed":{
                      "horizontal":861.641,
                      "isGround":0,
                      "vertical":0
                    },
                    "departure":{
                      "iataCode":"DJE",
                      "icaoCode":"DTTJ"
                    },
                    "arrival":{
                      "iataCode":"ORY",
                      "icaoCode":"LFPO"
                    },
                    "aircraft":{
                      "regNumber":"FGZHS",
                      "icaoCode":"B738",
                      "icao24":"3964F2",
                      "iataCode":"B738"
                    },
                    "airline":{
                      "iataCode":"TO",
                      "icaoCode":"TVF"
                    },
                    "flight":{
                      "iataNumber":"TO3875",
                      "icaoNumber":"TVF3875",
                      "number":"3875"
                    },
                    "system":{
                      "updated":"1543087861",
                      "squawk":"7376"
                    },
                    "status":"started"
                  }
                ]
              }
              

              Would obj.aircraft[0].geography
              not be an object ? with keys latitude,longitude etc ?

              1 Reply Last reply
              0
              • F filipdns

                @Christian-Ehrlicher I try to work with it like array:

                var obj =JSON.parse(res)
                console.log(obj.aircraft[0].geography)

                but the return message is [object Object]...

                kshegunovK Offline
                kshegunovK Offline
                kshegunov
                Moderators
                wrote on last edited by
                #13

                Firstly, what is this language? JS?
                Secondly, what is JSON in your code and where does it come from?

                Read and abide by the Qt Code of Conduct

                F 1 Reply Last reply
                0
                • kshegunovK kshegunov

                  Firstly, what is this language? JS?
                  Secondly, what is JSON in your code and where does it come from?

                  F Offline
                  F Offline
                  filipdns
                  wrote on last edited by
                  #14

                  @kshegunov Hello,

                  Yes, it's JS language to get the network response.

                  the JSON response is come from http://aviation-edge.com

                  with request like http://aviation-edge.com/v2/public/flights?key=2a8619-db5a5c&regNum=ECMJT

                  kshegunovK 1 Reply Last reply
                  0
                  • F filipdns

                    @kshegunov Hello,

                    Yes, it's JS language to get the network response.

                    the JSON response is come from http://aviation-edge.com

                    with request like http://aviation-edge.com/v2/public/flights?key=2a8619-db5a5c&regNum=ECMJT

                    kshegunovK Offline
                    kshegunovK Offline
                    kshegunov
                    Moderators
                    wrote on last edited by
                    #15

                    I am now completely confused. How and why is this JS executed and what relation does it bear to Qt? Is this a QML function?

                    Read and abide by the Qt Code of Conduct

                    F 1 Reply Last reply
                    0
                    • kshegunovK kshegunov

                      I am now completely confused. How and why is this JS executed and what relation does it bear to Qt? Is this a QML function?

                      F Offline
                      F Offline
                      filipdns
                      wrote on last edited by
                      #16

                      @kshegunov Hi, it has no link with qt, it's just in case some one can help me to parse JSON with keys.

                      But did what I need parsing in JS but it's not very beautiful code like it is example:

                                      res=doc.responseText//JS.data(doc.responseText)
                                      //console.log(res)
                                      //var obj =JSON.parse(res)
                                      var error="{\"error\": \"No Record Found or Flight not currently detected by receivers. \" }"
                                      if(res!==error)
                                      {
                                          var res1=res.replace("[","")
                                          var res2=res1.replace("{","")
                                          var res3=res2.split("{")
                                          var res4=res3[1]
                                          var res5= res4.split(",")
                                          var res6=res5[0]+res5[1]+res5[2]+res5[3]
                                          var res7=res6
                                          var res8=res7.replace("\n","")
                                          var res9=res8.replace("            ","")
                                          var res10=res9.replace("\"","")
                                          var res11=res10.split(":")
                                          var res12=res11[0].replace("\"","") //text: latitude
                                          var res13=res11[1].split("\n")
                                          var res14=parseFloat(res13[0])      //valeur latitude
                                          var res15=res13[1].replace("            \"","")
                                          var res16=res15.replace("\"","")    //text longitude
                                          var res17=parseFloat(res11[2].split("\n")[0])// valeur longitude
                                          var res18=parseInt(parseFloat(res11[3].split("\n")[0])*3.28084/100) // valeur altitude
                                          var res19 = parseInt(res11[4].split("\n")[0]) // valeur cap
                      
                      1 Reply Last reply
                      0
                      • F filipdns

                        Hello,

                        I'm trying to parse value from JSON file:

                        [ { "geography": { "latitude": 51.1392, "longitude": 11.1481, "altitude": 11280.5, "direction": 68.9 }, "speed": { "horizontal": 805.37, "isGround": 0, "vertical": -3.90144 }, "departure": { "iataCode": "BVA", "icaoCode": "LFOB" }, "arrival": { "iataCode": "CIA", "icaoCode": "LIRA" }, "aircraft": { "regNumber": "EIGDT", "icaoCode": "B738", "icao24": "", "iataCode": "B738" }, "airline": { "iataCode": "FR", "icaoCode": "RYR" }, "flight": { "iataNumber": "FR92QB", "icaoNumber": "RYR92QB", "number": "92QB" }, "system": { "updated": "1543065538", "squawk": "1127" }, "status": "en-route" }, { "geography": { "latitude": 43.4357, "longitude": 18.9397, "altitude": 11280.5, "direction": 136 }, "speed": { "horizontal": 914.949, "isGround": 0, "vertical": -5.20192 }, "departure": { "iataCode": "BVA", "icaoCode": "LFOB" }, "arrival": { "iataCode": "SKG", "icaoCode": "LGTS" }, "aircraft": { "regNumber": "EIEKI", "icaoCode": "B738", "icao24": "4CA808", "iataCode": "B738" }, "airline": { "iataCode": "FR", "icaoCode": "RYR" }, "flight": { "iataNumber": "FR3094", "icaoNumber": "RYR3094", "number": "3094" }, "system": { "updated": "1543065479", "squawk": "664" }, "status": "en-route" } ]
                        

                        with

                        
                           QByteArray data= reply->readAll();
                           QString datastring = QString::fromStdString(data.toStdString());
                            //qDebug()<<data;
                        
                            bool ok;
                            // datastring is a QString containing the JSON data
                            QtJson::JsonObject result = QtJson::parse(datastring, ok).toMap();
                        
                            if(!ok) {
                              qFatal("An error occurred during parsing");
                            }
                        
                            qDebug() << "latitude:" << result["latitude"].toString();
                        

                        but the result say only:

                        latitude: ""

                        What I did wrong?

                        [Moved to General and Desktop ~kshegunov]

                        Taz742T Offline
                        Taz742T Offline
                        Taz742
                        wrote on last edited by
                        #17

                        @filipdns
                        It is not a valid json file. https://forum.qt.io/topic/64314/json-access-data-in-multidimensional-arrays/8

                        Do what you want.

                        F 1 Reply Last reply
                        3
                        • Taz742T Taz742

                          @filipdns
                          It is not a valid json file. https://forum.qt.io/topic/64314/json-access-data-in-multidimensional-arrays/8

                          F Offline
                          F Offline
                          filipdns
                          wrote on last edited by
                          #18

                          @Taz742 thank you, I will stay with my poor code then lol

                          aha_1980A 1 Reply Last reply
                          0
                          • F filipdns

                            @Taz742 thank you, I will stay with my poor code then lol

                            aha_1980A Offline
                            aha_1980A Offline
                            aha_1980
                            Lifetime Qt Champion
                            wrote on last edited by
                            #19

                            @filipdns

                            Did you read the post @Taz742 linked?

                            Your top-level structure is a JSON array, so you must convert the document to a QJsonArray, not a QJsonObject.

                            Using a QJsonArray should work for you, too.

                            Qt has to stay free or it will die.

                            F 1 Reply Last reply
                            1
                            • aha_1980A aha_1980

                              @filipdns

                              Did you read the post @Taz742 linked?

                              Your top-level structure is a JSON array, so you must convert the document to a QJsonArray, not a QJsonObject.

                              Using a QJsonArray should work for you, too.

                              F Offline
                              F Offline
                              filipdns
                              wrote on last edited by filipdns
                              #20

                              @aha_1980 Hello, I start to read yes, I'm trying to understand how do that in js, I found documentation on QJsonArray only for c++ at the moment

                              kshegunovK 1 Reply Last reply
                              0
                              • F filipdns

                                @aha_1980 Hello, I start to read yes, I'm trying to understand how do that in js, I found documentation on QJsonArray only for c++ at the moment

                                kshegunovK Offline
                                kshegunovK Offline
                                kshegunov
                                Moderators
                                wrote on last edited by kshegunov
                                #21

                                In JS you just parse it, as it's a natively supported.

                                var myJson = JSON.eval(jsonText);
                                

                                If it's a valid json, then properties are available directly as any other java script object, or in your case:

                                var obj =JSON.parse(res);
                                console.log("Latitude: " + obj.aircraft[0].geography.latitude);
                                

                                I still don't get the relevance, though.

                                Read and abide by the Qt Code of Conduct

                                1 Reply Last reply
                                2
                                • M Offline
                                  M Offline
                                  makcorps
                                  Banned
                                  wrote on last edited by
                                  #22
                                  This post is deleted!
                                  1 Reply Last reply
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