javascript array of arrays

Question

I have the following arrays:

var dates = new Array();
var answers = new Array();

Once Populated, they will be the same length. What I need is an array that pair the same index values of the arrays. Like so:

var pairedArray = new Array();
//pairedArray should have the form: [[dates[0], answers[0]], [dates[1], answers[1]], ...., [dates[n-1], answers[n-1]]]

e.g.

data: [
            [Date.UTC(2010, 0, 1), 29.9], 
            [Date.UTC(2010, 2, 1), 71.5], 
            [Date.UTC(2010, 3, 1), 106.4]
        ]

How is this possible given that I have two arrays of the same length, answers and dates that are already populated?

Just a minor nitpick - in general, [] notation is way more awesome than new Array() — hugomg
– hugomg, Commented Aug 29, 2011 at 20:33

James Montagne · Accepted Answer · 2011-08-29 20:06:37Z

4

If you know they are always the same length, simply loop through one and add both to the result:

var data = [];

for(var i=0; i<dates.length; i++){
    data.push([dates[i], answers[i]]);
}

answered Aug 29, 2011 at 20:06

James Montagne

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user113716 · Accepted Answer · 2011-08-29 20:14:49Z

2

var data = $.map(dates, function(v,i) { return [ [ v,answers[i] ] ]; });

You can use the jQuery.map()^[docs] method, but you need to double-wrap the returned Array because when $.map gets an Array, it performs a concat.

answered Aug 29, 2011 at 20:14

user113716

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Darin Dimitrov · Accepted Answer · 2011-08-29 20:06:05Z

1

var firstArray = ...
var secondArray = ...
if (firstArray.length === secondArray.length) {
    var result = [];
    for (var i = 0; i < firstArray.length; i++) {
        result.push({ [ firstArray[i], secondArray[i] ] });
    }
    // TODO: do something with the result
}

answered Aug 29, 2011 at 20:06

Darin Dimitrov

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1 Comment

James Montagne Over a year ago

Don't think that will work with the {} unless you give the property a name {something: [...]}

ShankarSangoli · Accepted Answer · 2011-08-29 20:08:28Z

0

Try this

var dates = new Array();
var answers = new Array();
var pairedArray = new Array();

$.each(dates, function(i){
   pairedArray.push([ dates[i], answers[i] ]);
});

answered Aug 29, 2011 at 20:08

ShankarSangoli

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