JavaScript remove array

Question

I tried doing delete weapons[i]; but even do when I do weapons.length I still get 1. Even though it should be 0. How do I definitely remove an array from weapons[] array?

I comb over the weapons array by doing this:

        for (var i = 0, setsLen = weapons.length; i < setsLen; ++i ) {

             var searchWeapon = weapons[i].split("|");
             // console.log('['+i+'] >> Weapon ID: ' + searchWeapon[0] + ' | Y: ' + searchWeapon[1] + ' | X: ' + searchWeapon[2]);    
             if (searchWeapon[1] == Y && searchWeapon[2] == X) { 
                delete weapons[i];
             }           
            }

and I store each array as 3|10|4 where 3 is weapon ID, 10 is Y, and 4 is X.

slifty · Accepted Answer · 2012-08-03 17:11:06Z

3

Check out the .splice method

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/splice

Using your example:

for (var i = 0, setsLen = weapons.length; i < setsLen; ++i ) {
  var searchWeapon = weapons[i].split("|");
  if (searchWeapon[1] == Y && searchWeapon[2] == X) { 
    weapons.splice(i,1);
  }           
}

edited Aug 3, 2012 at 17:11

answered May 2, 2011 at 23:31

slifty

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2 Comments

test Over a year ago

Thank you for this. Splice did the trick. Also Splice was a horrible movie.

Amjad Masad Over a year ago

Link to MDC not W3FOOLS. Splice

BrunoLM · Accepted Answer · 2011-05-02 23:30:08Z

3

Use splice

array.splice(index,howmany)

answered May 2, 2011 at 23:30

BrunoLM

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Comments

Marty · Accepted Answer · 2011-05-02 23:46:01Z

3

If your array doesn't need to be sorted, you could use array.pop() as it's extremely fast.

if(index == array.length-1) array.pop();
else array[index] = array.pop();

This method doesn't need to re-index everything after what you've splice()'d, so it remains quick whether your array has a length of 5 or 350,000.

edited May 2, 2011 at 23:46

answered May 2, 2011 at 23:35

Marty

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3 Comments

Oliver Moran Over a year ago

Nice piece of code. But is this meaningfully faster than splice in a real-world context?

Marty Over a year ago

Yes.. A lot faster. Well, depending on the length of your array. pop() is always the same speed whereas splice gets slower with the length of the array.

Marty Over a year ago

No probs.. It's more something to keep in mind with game dev when you're listing 500-1000 projectiles and stuff haha.

Dr.Molle · Accepted Answer · 2011-05-02 23:55:50Z

2

Additional to the answers above: you should walk the array from the end to the start, otherwise you'll miss elements inside the loop if a item has been removed. Demo: http://jsfiddle.net/doktormolle/2f9Ye/

edited May 2, 2011 at 23:55

answered May 2, 2011 at 23:35

Dr.Molle

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Comments

Matt Greer · Accepted Answer · 2011-05-02 23:31:14Z

0

deleteing an array element leaves a hole behind with undefined left in the element's place. You probably want to use Array.splice.

var myArray = [1,2,3];
delete myArray[1]; // myArray is now [1, undefined, 3];

var myArray2 = [1,2,3];
myArray2.splice(1,1); // myArray2 is [1, 3]

answered May 2, 2011 at 23:31

Matt Greer

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Comments

Oliver Moran · Accepted Answer · 2011-05-02 23:35:51Z

0

To remove an element from an array use the splace method. Example:

var myArr = ["apple", "orange", "pear"];
alert(myArr.length); // 3
myArr.splice(1,1); // start at 1th index (i.e 2nd element), remove 1 element
alert(myArr.length); // 2
for (var i=0; i<myArr.length; i++) alert(myArr[i]); // "apple", "pear"

answered May 2, 2011 at 23:35

Oliver Moran

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1 Comment

Oliver Moran Over a year ago

LOLs. Yes, of course: Array.prototype.splace = Array.prototype.splice;

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