Reach the spesific element of Json Array
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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 ? "," : ""); } } } } -
@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" -
@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
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@suslucoder said in Reach the spesific element of Json Array:
qDebug() << inner_data[0].toString(); // "integer"
qDebug() << inner_data[1].toString(); // "0" -
@suslucoder
QJsonValueis something which behaves like aQVariant. It can hold any of the (6) types returned byQJsonValue::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 -
@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 wellI 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" } } -
@suslucoder
I don't really know what your latest question is.Forinner_data[1].toString().toInt()it is pointless to convert to string and then to integer, as I wrote earlier you might as well goinner_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(); ... } -
@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.
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@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 statementsBut it prints
0 0 0 1 1 1 13 13 13 -
@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. -
@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....
