Question

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Javascript - create array index and access

rated 0 times [ 3] [ 6] / answers: 1 / hits: 16471 / 12 Years ago, sat, april 28, 2012, 12:00:00

I am looking to create a simple array using a time stamp for the index so that I can access the values by timestamp without iterating through the array, however I am struggling!

I need to be able to set 2 values for each row.

For example:

var myarray = [];

var test1 = 'hello'

var test2 = 'world'



myarray[timestamp] = [test1, test2];

So for a given timestamp e.g. 12345678, how could I access the value of test2?

Appreciate any thoughts and advice.

Regards, Ben.

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cristinadomoniquel

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answered 12 Years ago yulissamirandah · Accepted Answer

If you use an array that way, you'll end up with an array containing a large amount of undefined values:

var myarr = [];

myarr[1000] = 'hello';

console.log(myarr.length); //=> 1001 

console.log(myarr[0]); //=> undefined

console.log(myarr[999]); //=> undefined

So, you may want to use an object for that and use some kind of sorting. For example

var myobj = {}, timestamp = new Date().getTime();

myobj[timestamp] =   ['hello','world'];

myobj[timestamp+1] = 'how are we today?';



function retrieveSorted(obj){

  var keys = Object.keys(obj).sort(), key, ret = [];

  while(key = keys.shift()){

    ret.push(obj[key]);

  }

  return ret;

}



var sorted = retrieveSorted(myobj); 

   //=> [[hello, world], how are we today?]

myobj[timestamp][1]; //=> world