Reach the spesific element of Json Array

[deleted286]

Here is my example Json File. I've read my json given the code before. But i have a question.
How can i reach specificly Gps id 0 which is the 1st element of GPS Id array.
I've try to keep that values in a vector, and then get but it will be too complicated.
Im open to any suggestion

{
   "A":[
      {
         "GPS":[
            {
               "GPS ID":[
                  "integer",
                  "0"
               ],
               "GPS Mod":[
                  "integer",
                  "1"
               ],
               "GPS Utc":[
                  "float",
                  "2"
               ],
               "GPS Latitude":[
                  "float",
                  "3"
               ],
               "GPS Longitude":[
                  "float",
                  "4"
               ]
  
            }
         ]

    QByteArray data = file.readAll();
    QJsonDocument doc = QJsonDocument::fromJson(data);

    QJsonObject root = doc.object();
    QJsonArray tlmtArray = root.value("A").toArray();

    for(int i = 0; i < tlmtArray.size(); ++i)
       {
           QJsonObject obj = tlmtArray[i].toObject();
           QJsonArray gps_array = obj.value("GPS").toArray();

    for(int j = 0; j < gps_array.size(); ++j)
        {
            QJsonObject gps_obj = gps_array[j].toObject();

            for(QJsonObject::const_iterator cit = gps_obj.constBegin(); cit != gps_obj.constEnd(); ++cit)
            {
               // qDebug() << cit.key().toStdU16String() <<  ": (";

                QJsonArray inner_data = cit.value().toArray();

                    if(inner_data[0] == "float")
                    {
                       // qDebug() << inner_data[0].toString().toStdU16String() << (0 < inner_data.size()-1 ? "," : "");

                    QVector<int> index;
                    index << inner_data[1].toString().toInt();
                  //  qDebug() << index;
                    if(index[0] ==5 )
                    {
                        qDebug() << index[0];
                        gps[index[0]].f;
                    }

                    }


                   else if (inner_data[0] == "integer")
                    {

                       // qDebug() << inner_data[0].toString().toStdU16String() << (0 < inner_data.size()-1 ? "," : "");
                    }

            }

        }

    }

[JonB]

@suslucoder said in Reach the spesific element of Json Array:

How can i reach specificly Gps id 0 which is the 1st element of GPS Id array.

// recognise "GPS ID" among `for(QJsonObject::const_iterator cit = gps_obj.constBegin()`
// you cannot recognise "GPS ID" as the "first" item in the object in the "GPS" array,
// as JSON keys in an object have no order
if (cit.key() == "GPS ID")

// or, access it directly:
cit = gps_obj["GPS ID"]

QJsonArray inner_data = cit.value().toArray();
inner_data[0];  // "integer"
inner_data[1];  // "0"

[deleted286]

@JonB this works for me, but i want to ask something more, if it isnt problem

                 if (cit.key() == "GPS ID")
                 {
                     QJsonArray inner_data = cit.value().toArray();
                    qDebug() <<  inner_data[0];  // "integer"
                    qDebug() <<  inner_data[1];  // "0"
                 }

My output is like:

QJsonValue(string, "integer")
QJsonValue(string, "0")

Cant i get it just integer and 0

[J.Hilk]

@suslucoder said in Reach the spesific element of Json Array:

qDebug() << inner_data[0].toString(); // "integer"
qDebug() << inner_data[1].toString(); // "0"

[deleted286]

@J-Hilk i did it before you wrote and it works. Thank you

[JonB]

@suslucoder
QJsonValue is something which behaves like a QVariant. It can hold any of the (6) types returned by QJsonValue::Type QJsonValue::type() .

You can use any of the QJsonValue::is...() methods to test for a particular type.

If you know what your type is in advance, or you test it as above to make sure, for your case you can use:

QJsonValue("integer").toString();  // `"integer"`, as a string
QJsonValue("0").toInt();  // `0`, as an integer

[deleted286]

@JonB well, thank you so much

What if i want to short this code... Im trying to give or operand like

inner_data[1].toString().toInt()         // it print the 0 for 3 times and the others as well

I know it isnt healthy for writing much more if statements but i foul up

if (cit.key() == "GPS ID" || cit.key() == "GPS Mod" || cit.key() == "GPS Uydu Sayısı")
                        {
                            QJsonArray inner_data = cit.value().toArray();
                            gps[inner_data[1].toString().toInt()].i;  // "0"

                        }

                 ```
                if (inner_data[0] == "integer")
                    {

                     if (cit.key() == "GPS ID)
                     {
                         QJsonArray inner_data = cit.value().toArray();
                         gps[inner_data[1].toString().toInt()].i;  // "0"

                     }

                     if (cit.key() == "GPS Mod")
                     {
                         QJsonArray inner_data = cit.value().toArray();
                         gps[inner_data[1].toString().toInt()];

                     }

                     if (cit.key() == "GPS Uydu Sayısı")
                     {
                         QJsonArray inner_data = cit.value().toArray();
                         gps[inner_data[1].toString().toInt()].i;  // "0"

                     }


                    }

[JonB]

@suslucoder
I don't really know what your latest question is.

For inner_data[1].toString().toInt() it is pointless to convert to string and then to integer, as I wrote earlier you might as well go inner_data[1].toInt().

Yes you can do all 3 via

if (cit.key() == "GPS ID" || cit.key() == "GPS Mod" || cit.key() == "GPS Uydu Sayısı")
{
    QJsonArray inner_data = cit.value().toArray();
    int intValue = inner_data[1].toString().toInt();
    ...
}

[Christian Ehrlicher]

@JonB said in Reach the spesific element of Json Array:

wrote earlier you might as well go inner_data[1].toInt()

No because the json contains a string, not an integer. The json is 'wrong' in this way - when an integer should be stored/read then it should be stored as integer and not as string.

[deleted286]

@JonB
When i wrote it with ||

and wants to print out

inner_data[1].toString.toInt()

I expect that it should give me

0 
1 
13       like i do it with seperate if statements

But it prints

0 0 0
1 1 1
13 13 13

[JonB]

@Christian-Ehrlicher
You are right. I had not fully noticed the "0" string-type (and similarly with the other numbers).

@suslucoder
Whatever produces our JSON (you? something else?) would be better outputting the numbers as numbers (no quotes) rather than as strings.

If the JSON had

"GPS ID":[
                  "integer",
                  0
               ],

then you could go inner_data[1].toInt(). However if it is

"GPS ID":[
                  "integer",
                  "0"
               ],

then you must indeed go inner_data[1].toString().toInt(). I have corrected my earlier accordingly.

[JonB]

@suslucoder said in Reach the spesific element of Json Array:

I expect that it should give me

That is what it will do.

But it prints

Sounds like you are printing the same value 3 times each time. No idea why you would do that, or what you would expect. If you have 3 prints (or 9 prints), that is what you will get....

[deleted286]

@JonB I produced my Json. It make sense i will edit my json and write without " "