Splicing a string indexed array in JavaScript

Question

I have a string indexed array that I would like to remove an item from.

Consider the following example code:

    var arr = new Array();       
    arr[0] = "Zero";
    arr[1] = "One";
    arr[2] = "Two";
    arr.splice(1, 1);

    for (var index in arr)
        document.writeln(arr[index] + " ");

    //This will write: Zero Two

    var arr = new Array();
    arr["Zero"] = "Zero";
    arr["One"] = "One";
    arr["Two"] = "Two";

    arr.splice("One", 1); //This does not work
    arr.splice(1, 1); //Neither does this

    for (var index in arr)
        document.writeln(arr[index] + " ");

    //This will write: Zero One Two

How do I remove "One" from the second example like I did in the first?

possible duplicate of Find all matching regex patterns and index of the match in the string — Gajus
– Gajus, Commented Sep 13, 2015 at 20:09

Paolo Bergantino · Accepted Answer · 2009-06-04 06:40:08Z

20

The proper way to do this is not with an Array but an object:

var x = {};
x['Zero'] = 'Zero';
x['One'] = 'One';
x['Two'] = 'Two';
console.log(x); //  Object Zero=Zero One=One Two=Two
delete x['One'];
console.log(x); //  Object Zero=Zero Two=Two

answered Jun 4, 2009 at 6:40

Paolo Bergantino

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3 Comments

Paolo Bergantino Over a year ago

@Daniel - no it doesn't, that's not modifying the array. Do arr.length after adding your value and before deleting it.

Paolo Bergantino Over a year ago

@Daniel You are confusing Objects and Arrays, and then within arrays the differences between delete vs splice: stackoverflow.com/questions/500606/…

Daniel Over a year ago

No, not confusing. Just did not know how it works. But the link you posted gives a good explanation. Very helpful in this threat.

Fabien Ménager · Accepted Answer · 2009-06-04 06:38:05Z

5

Once an Array has string keys (or numbers that don't follow), it becomes an Object.

An object doesn't have the splice method (or not the same as Array). You have to write your own, by making a new object and copy into it the key you want to keep.

But be careful ! The keys are not always ordered in the same way they were added in the object ! It depends on the browser.

answered Jun 4, 2009 at 6:38

Fabien Ménager

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