Remove Duplicate Items from Array

[GerssonDelgado]

I frecuently receive information from customers (image below)
I need to remove duplicate numbers

How can I create a new array without duplicated items
any help will be appreciate

[femkeblanco · Accepted solution]

function removeDuplicate(a) {
    for (var i = 0; i < a.length; i++) {
        for (var j = 0; j < a.length; j++) {
            if (i != j && a[i] == a[j]) {
                a.splice(j, 1);
            }
        }
    }
    return a;
}

var array1 = [1, 1, 1, 2, 2, 2, 3, 3, 3];
var array2 = removeDuplicate(array1);
alert( array2 );  // 1,2,3

[GerssonDelgado]

Awesome! Thanks in advance !!!

Gdelgado

[CarlosCanto]

sorry I don't mean harm but this array breaks the algo

var array1 = [2, 3, 1, 2, 2, 1, 3, 3, 2]; // returns 3,1,2,3

[femkeblanco]

Oops. Thanks for the catch.

What about

function removeDuplicate(a) {
    for (var i = a.length-1; i > -1; i--) {
        for (var j = 0; j < a.length; j++) {
            if (i != j && a[i] == a[j]) {
                a.splice(j, 1);
            }
        }
    }
    return a;
}
var array1 = [2, 3, 1, 2, 2, 1, 3, 3, 2];
var array2 = removeDuplicate(array1);
alert( array2 );  // 1,3,2

Alternatively

function removeDuplicate(a){
    var b = [];
    for (var i = 0; i < a.length; i++) {
        var duplicate = (function () {
            for (var j = 0; j < b.length; j++) {
                if (b[j] == a[i]) {
                    return true;
                }
            }
            return false;
        } () );
        if (!duplicate) {
            b.push(a[i])
        }
    }
    return b;
}
var array1 = [2, 3, 1, 2, 2, 1, 3, 3, 2];
var array2 = removeDuplicate(array1);
alert( array2 );  // 2,3,1

[CarlosCanto]

both versions work!

[CarlosCanto · Accepted solution]

I usually make a "map", meaning adding each array value to an object. Since you can't have duplicate object keys, each duplicate value would replace it's previous value if it already exists

var map = {};

var arr = [1,2,3,1,2,3];

for (var a=0; a<arr.length; a++) {
    map[arr[a]] = arr[a]; // {"1":1, "2":2, "3":3}
}

var unique = [];

for (var b in map) {
    unique.push(map[b]);
}

alert(unique);

[Disposition_Dev]

this is my approach as well. feels nice and tidy.

[GerssonDelgado]

Thank you all for your support!! 🙂