Read JSON response in JQuery

Question

This is my json response

{"COLUMNS":["LABEL1", "LABEL2", "RATE1", "RATE2"], "DATA":[["tps", "tvq", 10.0, 20.0]]} 

And I want to be able to loop only over the DATA element.

I don't have any code because I have no clue how to do this. Just learning this new language.

Answer 1

// response.DATA is an array with just one element
var dataElements = response.DATA;
// The first element in that array is another array containing your data
var firstData = dataElements[0];
// Loop through and access each individual element
for (var i = 0; i < firstData.length; i++) {
 alert(firstData[i]);
}

Answer 2

for(var i in response.DATA){
 alert(response.DATA[i];
}

Answer 3

If there are only arrays inside the DATA and you need each array, then do it like this:

for(var i in response.DATA){
 alert(response.DATA[i]);
}

Otherwise if you want all the values tps, tvq, 10.0, and 20.0, then do it like this:

for(var i in response.DATA[0]){
 alert(response.DATA[0][i]);
}

---

Update

var arrData = response.DATA[0],
 sizeOfData = arrData.length,
 i = 0;
for(i; i < sizeOfData; i++){
 alert(arrData[i]);
}

• lonesomeday: That won't work usefully (since DATA[0] is the only element in DATA and is an array itself) and it's not good to loop through arrays with for..in loops.
• Shef: @lonesomeday: I had edited already. Any benchmarks on the speed between for .. in and for, please enlighten me.
• lonesomeday: Speed isn't the isssue. Things like Array.prototype.forEach = function(){} are the problem. for..in should be used for looping over object properties; for for array elements.