Getting an union of two arrays in jQuery

Question

Say I have an array of [34,35,45,48,49] and another array of [48,55]. How can I get a resulting array of [34,35,45,48,49,55]?

Answer 1

function unique(arrayName)
            {
                var newArray=new Array();
                label:for(var i=0; i<arrayName.length;i++ )
                {  
                    for(var j=0; j<newArray.length;j++ )
                    {
                        if(newArray[j]==arrayName[i]) 
                            continue label;
                    }
                    newArray[newArray.length] = arrayName[i];
                }
                return newArray;
            }

var arr1 = new Array(0,2,4,4,4,4,4,5,5,6,6,6,7,7,8,9,5,1,2,3,0);
var arr2= new Array(3,5,8,1,2,32,1,2,1,2,4,7,8,9,1,2,1,2,3,4,5);
var union = unique(arr1.concat(arr2));

Answer 2

If you don't need to keep the order, and consider 45 and "45" to be the same:

function union_arrays (x, y) {
  var obj = {};
  for (var i = x.length-1; i >= 0; -- i)
     obj[x[i]] = x[i];
  for (var i = y.length-1; i >= 0; -- i)
     obj[y[i]] = y[i];
  var res = []
  for (var k in obj) {
    if (obj.hasOwnProperty(k))  // <-- optional
      res.push(obj[k]);
  }
  return res;
}

alert(union_arrays([34,35,45,48,49], [44,55]));
// shows [49, 48, 45, 35, 34, 55, 44]

Answer 3

I would first concatenate the arrays, then I would return only the unique value.

You have to create your own function to return unique values. Since it is a useful function, you might as well add it in as a functionality of the Array.

In your case with arrays array1 and array2 it would look like this:

1. array1.concat(array2) - concatenate the two arrays
2. array1.concat(array2).unique() - return only the unique values. Here unique() is a method you added to the prototype for Array.

The whole thing would look like this:

jsFiddle example

Array.prototype.unique = function () {
    var r = new Array();
    o:for(var i = 0, n = this.length; i < n; i++)
    {
        for(var x = 0, y = r.length; x < y; x++)
        {
            if(r[x]==this[i])
            {
                continue o;
            }
        }
        r[r.length] = this[i];
    }
    return r;
}
    var array1 = [34,35,45,48,49];
    var array2 = [34,35,45,48,49,55];

      // concatenate the arrays then return only the unique values
    alert(array1.concat(array2).unique());

Answer 4

First set your two arrays. Merge them into a new array. Make the new array unique and then sort it.

var first = [34,35,45,48,49];
    var second = [48,55];
    var third = $.merge( $.merge([],first), second);
    var elem = $.unique(third).sort();
    alert(elem);