Question

I’ve got a JSON response that looks like this:

{
    "COLUMNS":["SETTING_NAME","SETTING_VALUE","COLOR"],
    "DATA": [
                ["setting_1",100.0,"yellow"],
                ["setting_2",150.0,"red"],
                ["setting_3",30.0,"green"],
                ["setting_4",11.0,"blue"]
            ]
 }

How do I find the ‘color’ for the setting ‘setting_4’? Acceptable solutions would either be am easy way to access the data, or a function to transform this into an exploded key/value array like

 [
     setting_1_value: '100', 
     setting_1_color: 'yellow', 
     setting_2_value: "150"
     ...
  ]

Answer 1

You can use this code to put the data into the type of data structure that you asked for:

var response = {"COLUMNS":["SETTING_NAME","SETTING_VALUE","COLOR"],
"DATA":[["setting_1",100.0,"yellow"],["setting_2",150.0,"red"],
["setting_3",30.0,"green"],["setting_4",11.0,"blue"]]};

var data = response.DATA;
var columns = response.COLUMNS;
var hash = {}, item, name, i;
var cols = {};

// remember order of columns
for (i = 0; i < columns.length; i++) {
    cols[columns[i]] = i;
}
// fetch data from correct column
for (i = 0; i < data.length; i++) {
    item = data[i];
    name = item[cols["SETTING_NAME"]];
    hash[name + "_value"] = item[cols["SETTING_VALUE"]];
    hash[name + "_color"] = item[cols["COLOR"]];
}
hash.num = data.length;

As you requested, this gives you a data structure like this so you can directly read any value you want:

{
    "setting_1_value":100,
    "setting_1_color":"yellow",
    "setting_2_value":150,
    "setting_2_color":"red",
    "setting_3_value":30,
    "setting_3_color":"green",
    "setting_4_value":11,
    "setting_4_color":"blue",
    "num":4
}

jsFiddle here: http://jsfiddle.net/jfriend00/HZmYN/ that generated this result.

Personally, I would rather use this code to parse it into this type of data structure:

var response = {"COLUMNS":["SETTING_NAME","SETTING_VALUE","COLOR"],
"DATA":[["setting_1",100.0,"yellow"],["setting_2",150.0,"red"],
["setting_3",30.0,"green"],["setting_4",11.0,"blue"]]};

var data = response.DATA;
var columns = response.COLUMNS;
var newData = [], item, obj, i, num, match;

var cols = {};

// remember order of columns
for (i = 0; i < columns.length; i++) {
    cols[columns[i]] = i;
}

for (i = 0; i < data.length; i++) {
    item = data[i];
    obj = {};
    obj.value = item[cols["SETTING_VALUE"]];
    obj.color = item[cols["COLOR"]];
    obj.name = item[cols["SETTING_NAME"]];
    match = obj.name.match(/\d+$/);
    if (match && match.length > 0) {
        obj.settingNumber = parseInt(match[0], 10);
    }
    newData.push(obj);
}

// now sort the array by the number in the name setting
newData.sort(function(a, b) {
    return(a.settingNumber- b.settingNumber);
});

And generates this data structure:

[
  {"value":100,"color":"yellow","name":"setting_1","settingNumber":1},
  {"value":150,"color":"red","name":"setting_2","settingNumber":2},
  {"value":30,"color":"green","name":"setting_3","settingNumber":3},
  {"value":11,"color":"blue","name":"setting_4","settingNumber":4}
]

Illustrated in this jsFiddle: http://jsfiddle.net/jfriend00/A23Jd/.

The reason I prefer this structure, is you can more easily access the “n” settings as an array of objects:

newData[0].color
newData[0].value
newData[0].name
newData[1].color
....

And, it’s easier to iterate through the various settings