Problem with indexOf on JavaScript array

Question

var allProductIDs = [5410, 8362, 6638, 6758, 7795, 5775, 1004, 1008, 1013, 1014, 1015, 1072, 1076, 1086, 1111, 1112, 1140];

lastProductID = 6758;

for some reason I get a -1 or I guess which is equivalent to not found for this:

alert(allProductIDs[allProductIDs.indexOf(lastProductID));

I can't figure out for the life of my why because it should find 6758 and that would be index 3. If it's index 3 then I should get back 6758 I would think.

For what it's worth, yes -1 means not found.

Nosredna
– Nosredna

2009-07-01 20:42:58 +00:00
Commented Jul 1, 2009 at 20:42 — Nosredna
– Nosredna, Commented Jul 1, 2009 at 20:42

No Idea For Name · Accepted Answer · 2014-12-23 12:10:51Z

5

.indexOf() is used for strings, not arrays.

Using regular Javascript you'll have to loop through the array until you find a match, or use the inArray() function of jQuery.

jQuery inArray()

edited Dec 23, 2014 at 12:10

No Idea For Name

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answered Jul 1, 2009 at 20:39

Mike Robinson

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6 Comments

PositiveGuy Over a year ago

nice. Was not aware of that. Is there a shortuct to having to use jQuery. such as can you use $.inArray() or something like that?

PositiveGuy Over a year ago

tried this but it loops infinitely and gives me a -1 every damn time: for(i = 0; i < numberOfImagesToDisplay; i++) { if (i > 0) { addIndex = productIDs.length + 1; } alert(allProductIDs[jQuery.inArray(lastProductID) + i]); productIDs[addIndex] = allProductIDs[jQuery.inArray(lastProductID) + i]; }

PositiveGuy Over a year ago

it also throws my program in an infinite loop! weird.

newacct Over a year ago

apparently arrays have .indexOf() in JavaScript 1.6 and later though: developer.mozilla.org/en/Core_JavaScript_1.5_Reference/…

Mike Robinson Over a year ago

@CoffeeAddict - It should have been "i < numberOfImagesToDisplay.length"

|

Scott Evernden · Accepted Answer · 2009-07-01 20:59:33Z

3

var allProductIDs = [5410, 8362, 6638, 6758, 7795, 5775, 1004, 1008, 1013, 1014, 1015, 1072, 1076, 1086, 1111, 1112, 1140];

lastProductID = 6758;

for (i in allProductIDs)
{
    if (allProductIDs[i] == lastProductID) {
        alert(allProductIDs[i] + " is at index " + i);
        break;
    }
}

or

i = $.inArray(lastProductID, allProductIDs)
alert(allProductIDs[i] + " is at index " + i);

answered Jul 1, 2009 at 20:59

Scott Evernden

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1 Comment

PositiveGuy Over a year ago

any idea why my program would be thrown into an infinite loop with the following : for(i = 0; i < numberOfImagesToDisplay; i++) { if (i > 0) { addIndex = productIDs.length + 1; } //alert(allProductIDs[jQuery.inArray(lastProductID) + i]); productIDs[addIndex] = allProductIDs[jQuery.inArray(lastProductID) + i]; }

timbo · Accepted Answer · 2009-07-01 20:40:23Z

0

Check your syntax too. You are missing an end bracket ..']'

answered Jul 1, 2009 at 20:40

timbo

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