Removing item from array by value in JavaScript giving unpredictable results

Question

I have this code for removing an item from an array by value in JS...

function remove_item(index){

    //log out selected array
    console.log('before >> ' + selected); //

    //log out item that has been requested to be removed
    console.log('removing >> ' + index);

    //remove item from array
    selected.splice( $.inArray(index,selected) ,1 );

    //log out selected array (should be without the item that was removed
    console.log('after >> ' + selected);

    //reload graph
    initialize();
}

This is what my array looks like...

selected = [9, 3, 6]

If I call remove_item(3) this is what gets logged out...

before >> 9,3,6
removing >> 3
after >> 9,3

After should be 9,6 not 9,3

I'm totally stumped on this as it sometimes works and sometimes doesn't...

For example I just tried remove_item(10) and this worked...

before >> 1,2,10
removing >> 10
after >> 1,2

I'm sure it has something to do with this line:

selected.splice( $.inArray(index,selected) ,1 );

Any help much appreciated.

wombleton · Accepted Answer · 2011-05-22 12:51:45Z

3

If it's inconsistent, sometimes the parameter index is a string, and sometimes it's a number.

$.inArray('3', arr) will return -1.

$.inArray(3, arr) will return 1.

[9, 3, 6].splice(-1, 1);  // removes last item from the array

See splice's docs.

You can make sure it's always a number by doing this:

//remove item from array
selected.splice( $.inArray(Number(index),selected) ,1 );

... or ...

function remove_item(index){
  index = Number(index);

answered May 22, 2011 at 12:51

wombleton

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1 Comment

kieran Over a year ago

That resolved it - I ended up going down a slightly different route of reconstructing the array by looping through selected elements which seems to work much better. But this resolved the question. Accepted. Thanks!

Bora · Accepted Answer · 2011-05-22 12:25:06Z

0

I tested your code and it works as intended.

I think you need to check your input array once more. Is it really [9,3,6] or do you expect it to be that?

answered May 22, 2011 at 12:25

Bora

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1 Comment

kieran Over a year ago

Yeah - logging it out is 9,3,6 100%

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