The best way to remove array element by value

Question

I have an array like this

arr = [\"orange\",\"red\",\"black\",\"white\"]

I want to augment the array object defining a deleteElem()<

Answer 1

The trick is to go through the array from end to beginning, so you don't mess up the indices while removing elements.

var deleteMe = function( arr, me ){
   var i = arr.length;
   while( i-- ) if(arr[i] === me ) arr.splice(i,1);
}

var arr = ["orange","red","black", "orange", "white" , "orange" ];

deleteMe( arr , "orange");

arr is now ["red", "black", "white"]

Answer 2

The best way is to use splice and rebuild new array, because after splice, the length of array does't change.

Check out my answer:

function remove_array_value(array, value) {
    var index = array.indexOf(value);
    if (index >= 0) {
        array.splice(index, 1);
        reindex_array(array);
    }
}
function reindex_array(array) {
   var result = [];
    for (var key in array) {
        result.push(array[key]);
    }
    return result;
}

example:

var example_arr = ['apple', 'banana', 'lemon'];   // length = 3
remove_array_value(example_arr, 'banana');

banana is deleted and array length = 2

Answer 3

Here you go:

arr.deleteElem = function ( val ) {
    for ( var i = 0; i < this.length; i++ ) {
        if ( this[i] === val ) {
            this.splice( i, 1 );
            return i;
        }
    }
};

Live demo: http://jsfiddle.net/4vaE2/3/

The deleteElem method returns the index of the removed element.

var idx = arr.deleteElem( 'red' ); // idx is 1

Answer 4

Array.prototype.deleteElem = function(val) {
    var index = this.indexOf(val); 
    if (index >= 0) this.splice(index, 1);
    return this;
}; 
var arr = ["orange","red","black","white"];
var arr2 = arr.deleteElem("red");

Answer 5

Or simply check all items, create a new array with non equal and return it.

var arr = ['orange', 'red', 'black', 'white'];

console.info('before: ' + JSON.stringify(arr));

var deleteElem = function ( val ) {
    var new_arr = [];
    for ( var i = 0; i < this.length; i++ ) {
        if ( this[i] !== val ) {
            new_arr.push(this[i]);
        }
    }
    return new_arr;
};

arr = deleteElem('red');

console.info('after: ' + JSON.stringify(arr));

http://jsfiddle.net/jthavn3m/

Answer 6

My approach, let's see what others have to say. It supports an "equals" method as well.

 // Remove array value
 // @param {Object} val
 Array.prototype.removeByValue = function (val) {
    for (var i = 0; i < this.length; i++) {
       var c = this[i];
       if (c == val || (val.equals && val.equals(c))) {
          this.splice(i, 1);
          break;
       }
    }
 };

Read https://stackoverflow.com/a/3010848/356726 for the impact on iterations when using prototype with Array.