When reading QJsonArray it gives always 0
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I have 5 diferent QJsonArray which depends on single root. I want to read them from a file. I have the code below for it. I have 5,2 in A. But my code returns A = 0 always.
QJsonObject root = doc.object(); QJsonArray grvArray = root.value("A").toArray(); for(int i=0; i<grvArray.size(); i++ ) { QJsonObject subArray = grvArray[i].toObject(); qDebug() << "Abc:" << grvArray[i].toObject()["Abc"].toDouble(); } return a.exec(); }Here is my json
"A": [ { "Abc": "11,48855", "Max:": "6,3", "Min :": "5,3", "Kg": "7,4" } -
@suslucoder said in When reading QJsonArray it gives always 0:
Here is my json
If that's your JSON then it is invalid. Please post your real JSON content.
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@jsulm it is to long i wanted to cut them but i forgot some paranthesis.
Here is
{ "Genel":[ { "Dns Ivme Ktsy:":"41,123", "Dns Msf Ktsy:":"451,52", "Dnste Dumen:":"1,3", "Dnste Gaz:":"6,3", "Dnste Yks r Aci Lmt:":"5.1", "Dnste Yksls:":"78,56", "Gaz Alt Limit:":"454,555", "Gps Bekleme Aci":"9,3", "Ize Yklsm Msf:":"12,36", "Kesisme Aci:":"55.47", "Nkt Kabul:":"52,36", "Telemetri Sklk:":"1215,15", "Yksls r Aci Lmt:":"7,3" } ], "A":[ { "Abc":"11,48855", "Max:":"6,3", "Min:":"5,3", "Kg":"7,4" } ], "PID":[ { "Alcalis aci:":"2,3", "G D Kznc":"96,3", "G I Kznc:":"4,36", "G Kmt Lmt:":"74.6", "G P Kznc:":"4,25", "IAS D Kznc:":"21,541", "IAS I Kznc:":"69,3", "IAS P Kznc:":"5,36", "P D Kznc":"45", "P I Kznc:":"335", "P Kmt Kznc:":"254", "P P Kznc:":"22", "R D Kznc:":"6", "R I Kznc:":"5", "R Kmt Lmt:":"2", "R P Kznc:":"4", "Y D Kzncn:":"44,6", "Y I Kzncn:":"2,3", "Y Kmt Lmt:":"7,5", "Y P Kzncn:":"3,6", "Ykls D Kznc:":"7,32", "Ykls I Kznc:":"5,25", "Yksls Aci:":"7,3", "Yksls P Kznc:":"2,36", "Yon Aci:":"9,1", "Yon D Kznc:":"7,5", "Yon I Kznc:":"3,6", "Yon P Kznc:":"45.23" } ], "Servo":[ { "Alt Nkt:":"7,32", "Motor Yon :":"23,63", "Sag Ana Knt Aci orta:":"5,3", "Sag Ana Knt Alt Nkt:":"3,2", "Sag Ana Knt Orta Nkt:":"7,5", "Sag Ana Knt Ust Nkt:":"9,6", "Sag Ana Knt Yon:":"1,2", "Sag Arka Knt Aci orta:":"47,12", "Sag Arka Knt Alt Nkt:":"23,5", "Sag Arka Knt Orta Nkt:":"78,21", "Sag Arka Knt Ust Nkt:":"12,25", "Sag Arka Knt Yon:":"2,5", "Sol Ana Knt Aci orta:":"7,5", "Sol Ana Knt Alt Nkt:":"7,5", "Sol Ana Knt Orta Nkt:":"1,2", "Sol Ana Knt Ust Nkt:":"9,2", "Sol Ana Knt Yon:":"4,5", "Sol Arka Knt Aci orta:":"", "Sol Arka Knt Alt Nkt:":"", "Sol Arka Knt Orta Nkt:":"", "Sol Arka Knt Ust Nkt:":"", "Sol Arka Knt Yon:":"", "Ust Nkt:":"77,23" } ], "Seyir":[ { "Mncnk Klks Btrm Sure:":"23,21", "Mncnk Klks Btrm Yksklk:":"4,21", "Motor Kpt Lmt ":"12,36", "Perdo Hiz:":"231,56", "Perdo Sakinma Aci":"12,25", "Pitch Trim:":"2,3", "Prst Rota Zmn Asim:":"7,36", "Roll Trim:":"4,21", "Seyir Hizi IAS:":"23,15", "Seyir Zmn Asim:":"4,12", "Stab Zmn Asim:":"45566", "Yaw Trim:":"4,26" } ] } -
do not localize your json, stick with the norm and use a dot as a separator for your double/floats
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@suslucoder said in When reading QJsonArray it gives always 0:
"11,48855",
This is a string, no double.
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@J-Hilk said in When reading QJsonArray it gives always 0:
do not localize your json, stick with the norm and use a dot as a separator for your double/floats
I use dot but it wont change anything. I cant read
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This post is deleted!
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@Christian-Ehrlicher but 5.0 is double? I've changed the value
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@suslucoder said in When reading QJsonArray it gives always 0:
but 5.0 is double?
It's not
5.0but"5.0"and this is a string. See also QJsonValue::Type() -
@suslucoder JSON does not convert strings to numbers. So if a value is string and you try to read a double, it will always return 0.
A workaround for this is:
qDebug() << "Abc:" << grvArray[i].toObject()["Abc"].toVariant().toInt();Although it does come with it's problems.
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It's etchiness depends on particular case. In some applications, JSON is used as an internal format, where rules can be different than official ones. And being able to specify a number by either string or number is useful.
Plus, let's not forget JSON does not support integers at all. So if you want to specify an integer and be sure it won't be fuzzy, using a string is OK.
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I don't know where @suslucoder gets his JSON from. And I admit in my code I save/restore integers (C++ type) not floating point. But for integers at least I note that Qt JSON saves as a number, not as a string. So I imagine it would save a floating point similarly. Just saying.
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@JonB ı didnt get my json from anywhere. I create it by myself
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@sierdzio I did it like this way. But it cant read some datas still. What should be the reason? It reads the first and last element of 1 array. And then, didnt read the second item of an array. Read the 4.element of array 2. I didnt understand
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Since you created the json manually you're mixing
.and,. Use the proper json notation for doubles without quotes if you want that someone else will be able to read them and don't create such files manually. -
@Christian-Ehrlicher I have LineEdit. I take datas from line edit on my qui, and save those datas in txt file which is formatted json. I want to take float or double nums on line edit.
I have " " because line edit accept strings.
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@suslucoder said in When reading QJsonArray it gives always 0:
I have " " because line edit accept strings.
But you cant save strings in the same way as you save floats / doubles
or ints(edit: No ints).@Christian-Ehrlicher said in When reading QJsonArray it gives always 0:
It's not 5.0 but "5.0" and this is a string. See also QJsonValue::Type()
That's what @Christian-Ehrlicher said here
So you have to differentiate what is going to be stored in your Json.
(If you build your Json yourself -> strings with"....."and floats with.as separator to avoid read errors)You can save everything as string, but then you have to convert it when reading the values again (-> also works best when using a dot as separator. Not every locale supports
,as decimal separator. This is why you probably got0) -
@suslucoder
...Which is why I suggested you might choose to save/put in file41.123instead of string with quotes like your"41,123", then you will be storing a number and won't have to convert from a string....
