check if item in array1 exist in array2

Question

Having some problems here with arrays. I basically want to loop through array1, check which elements in that array exist in array2 and then return a new array containing all matches.

How would one do that?

Answer 1

This code is in pure javascript not with library

var fruits1 = ["Banana", "Pear"];
var fruits2 = ["Banana", "Orange", "Apple", "Mango"];
var fruits3 = [];

for (i=0; i< fruits1.length; i++)
   if (fruits2.indexOf(fruits1[i]) > -1)
     fruits3.push(fruits1[i]);

Answer 2

If you have unsorted arrays with different lengths, this will work too.

Create a function called intersect for example:

function intersect(arr1,arr2){
    //We need to know which array is the shortest to avoid useless loops
    if(arr2.length<arr1.length){
        var temp = arr1;
        arr1 = arr2;
        arr2 = temp;
    }
    // Now, we are sure arr1 is the shortest
    var result = [];
    for(var i = 0; i<arr1.length; i++){
        if(arr2.indexOf(arr1[i])>-1) result.push(arr1[i]);
    }
    return result;
}

This function takes 2 arrays as parameters, and no need to worry about their order.

Then you can call it and see the results:

var arr1 = [1,2,3,4,5];
var arr2 = [4,5,6,7,8,9,10,12];

var inter = intersect(arr1,arr2);
alert(inter);

JS Fiddle Demo

Answer 3

Vanilla Javascript

for(var x=0;x<array1.length;x++){
    for(var y=0;y<array2.length;y++){
        if ( array1[x] == array2[y] ) array3.push(array1[x]);
    }
}

Jquery version

$.each(array1, function(k,v){
    $.each(array2, function(k2,v2){
       if ( v == v2 ) array3.push(v2);
    });
});