Next index value of object in foreach

Question

i have this object called defined in my code as rates.rates:

{ AUD="1.4553",  BGN="1.9558",  BRL="3.5256"}

and i have the following $.each loop:

$.each( rates.rates, function( index, value ){

  console.log(index);

});

I've been trying without success to also console.log the next or the previous index (if they exist of course). Any help is really appreciated.

You can save the previous index in a variable. There's no way to get the next index. — Barmar
– Barmar, Commented Oct 13, 2016 at 9:06
Except that's poorly explained, why would you save the net index, for wich purpose? let us know, there is many possible answers depending on your final goal. — N.K
– N.K, Commented Oct 13, 2016 at 9:07
You can check the index against the total number of elements and 0 to see if they exists. — AshishJindal
– AshishJindal, Commented Oct 13, 2016 at 9:11
Your object syntax is wrong. It's key: value, not key=value — Barmar
– Barmar, Commented Oct 13, 2016 at 9:12
set a counter to 0 before the each, and then increment on each iteration of the each loop. This gives a pseudo-index for your loop. — gavgrif
– gavgrif, Commented Oct 13, 2016 at 9:12

Barmar · Accepted Answer · 2016-10-13 09:15:07Z

2

Instead of iterating over the object, get its keys as an array and iterate over that. Then you can add and subtract from the array index.

var keys = Object.keys(rates.rates);
$.each(keys, function(index, key) {
    var prevkey = index > 0 ? keys[index-1] : null;
    var nextkey = index < keys.length-1 ? keys[index+1] : null;
    console.log(prevkey, key, nextkey);
});

edited Oct 13, 2016 at 9:15

answered Oct 13, 2016 at 9:11

Barmar

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1 Comment

N.K Over a year ago

Best answer at the moment, just because it's what the OP's was asking for.

Vibhesh Kaul · Accepted Answer · 2016-10-13 09:18:20Z

0

JS objects have no defined order, they are (by definition) an unsorted set of key-value pairs.

But there's a way for you to do what you want.You can do it like this.

var keys=Object.keys(rates.rates);

for(vari=0; i<keys.length;i++)
{       
    console.log(i);  
}

edited Oct 13, 2016 at 9:18

answered Oct 13, 2016 at 9:06

Vibhesh Kaul

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Comments

P. Frank · Accepted Answer · 2016-10-13 09:58:15Z

0

You can get the next or prev with modulo. With this you can make a loop automatically.

Please try below:

rates={
    rates:{ "AUD":"1.4553",  "BGN":"1.9558",  "BRL":"3.5256"}
  };
var keys = Object.keys(rates.rates);
$.each(keys, function(index, key) {
    if(index == 0){index=keys.length};
    var prevkey = (index-1) % keys.length; 
    var nextkey = (index+1) % keys.length; 
    console.log(prevkey, key, nextkey);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

answered Oct 13, 2016 at 9:58

P. Frank

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