getting javascript error while iterating through array

Question

function sortproducts(filprodlist)
{
    var prod;
    var k = 0;
    for (i = 0; i < filprodlist.length; i++) {
        var k = i + 1;
        var p=filprodlist[i].EntityKey.substr(filprodlist[i].EntityKey.length - 1);
        var p2=filprodlist[k].EntityKey.substr(filprodlist[k].EntityKey.length - 1);
        if ( p>p2)  {
            temp = filprodlist[k];
            filprodlist[k] = filprodlist[i];
            filprodlist[i] = temp;
        }
    }
    rederProduct(filprodlist);
}

while executing above code getting following error TypeError: filprodlist[k] is undefined

it's answer is in other part of your code, show it

halkujabra
– halkujabra

2014-04-24 11:10:04 +00:00
Commented Apr 24, 2014 at 11:10 — halkujabra
– halkujabra, Commented Apr 24, 2014 at 11:10
Why aren't you using the built-in sort method?

Barmar
– Barmar

2014-04-24 11:12:45 +00:00
Commented Apr 24, 2014 at 11:12 — Barmar
– Barmar, Commented Apr 24, 2014 at 11:12

Satpal · Accepted Answer · 2014-04-24 11:11:09Z

1

Reason

On last iteration, when i is at last element of array. You are fetching are using var k = i + 1;, where k doesn't exists. Thus you are getting the error.

So Use

for (i = 0; i < filprodlist.length - 1; i++) {

instead of

for (i = 0; i < filprodlist.length; i++) {

answered Apr 24, 2014 at 11:11

Satpal

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Comments

Paul S. · Accepted Answer · 2014-04-24 11:15:17Z

Don't var inside loops, blocks don't have scope in JavaScript, var every variable you want to use in one var statement. End your loop when the highest index reaches the end (k). You can move k into the for's iterate step because you're really iterating with this, too.

function sortproducts(filprodlist) {
    var prod, i, k, p, p2, temp;
    for (i = 0, k = 1; k < filprodlist.length; ++i, ++k) {
        p =  filprodlist[i].EntityKey.substr(filprodlist[i].EntityKey.length - 1);
        p2 = filprodlist[k].EntityKey.substr(filprodlist[k].EntityKey.length - 1);
        if (p > p2)  {
            temp = filprodlist[k];
            filprodlist[k] = filprodlist[i];
            filprodlist[i] = temp;
        }
    }
    rederProduct(filprodlist);
}

A different way to do it is forget k all together, start from i = 1 and use i - 1 and i, this means you're iterating with less variables so it might be easier for you to follow the code in your mind.

Roman Hocke · Accepted Answer · 2014-04-24 11:13:11Z

0

Let's say filprodlist has 10 items. Then the items are indexed 0-9 and Your i goes through 0-9. In every iteration You define k = i + 1. So in the last iteration i = 9, k = 10 and You are trying to access filprodlist[10] which doesn't exist (returns undefined). Solution is in @Satpal's answer.

answered Apr 24, 2014 at 11:13

Roman Hocke

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