I have two arrays in javascript -:
var array1 = ['12','1','10','19','100'];
var array2 = ['12','10','19'];
I need to a method to get the unique from two arrays and put them in array3
Array3 should be -:
var array3 = ['1','100'];
Thanks for help.
var array3 = array1.filter(function(obj) { return array2.indexOf(obj) == -1; });
MDN on Array#filter: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/filter
Includes a polyfill for older browsers.
With a bit of ES6 magic it can be fairly concise. Note that we need to check both ways around in case there are unique items in either array.
const arr1 = [1, 2, 3, 4, 5];
const arr2 = [1, 3, 8];
let unique1 = arr1.filter((o) => arr2.indexOf(o) === -1);
let unique2 = arr2.filter((o) => arr1.indexOf(o) === -1);
const unique = unique1.concat(unique2);
console.log(unique);
// >> [2, 4, 5, 8]
arr2 contains an unique number, then it will not be added to unique.
var unique = [];
for(var i = 0; i < array1.length; i++){
var found = false;
for(var j = 0; j < array2.length; j++){ // j < is missed;
if(array1[i] == array2[j]){
found = true;
break;
}
}
if(found == false){
unique.push(array1[i]);
}
}
UPDATE The original post works but is not very fast, this implementation is a lot faster, this example uses only one array, but in the function you can easily pass any additional arrays to combine.
only a simple error check is done and more should be in place, use at own discretion, meant as working example only.
function Unique(array) {
var tmp = [];
var result = [];
if (array !== undefined /* any additional error checking */ ) {
for (var i = 0; i < array.length; i++) {
var val = array[i];
if (tmp[val] === undefined) {
tmp[val] = true;
result.push(val);
}
}
}
return result;
}
var unique = Unique([1, 2, 2, 6, 8, 5, 6, 8]);
Additionally this can be implemented as prototype of the Array object, changing the signature to
Array.prototype.Unique = function() {
var array = this;
...
}
and can be called like this:
var unique = [1, 2, 2, 6, 8, 5, 6, 8].Unique();
Something like this
var array1 = ['12','1','10','19','100'];
var array2 = ['12','10','19'];
var o = {};
for(var i in array1) {
o[i] = 1;
}
for(var i in array2) {
o[i] = 0;
}
var array3 = [];
for(var i in o) {
if(o[i] == 1) {
array3.push(i);
}
}
var array3 = array1.concat(array2);
array3 = array3.sort(function(a, b) { return a > b; });
array3 = array3.filter(function(num, index) { return num !== array3[index + 1]; });
array3 will have only unique values
this also does the job in two loops which is pretty inexpensive, it should be noted that sort() and filter() are ECMA5 functions and not supported in older browsers, also i usually use a library like underscore so i don't have rewrite these functions for each project i work on, underscore has a .unique() method which obviously is less code and more clearly states the intention of the operation
var array1 = ['12','1','10','19','100'];
var array2 = ['12','10','19'];
var newArr,temp,temp1;
temp=array1.filter(function(el)
{
return arr2.indexOf(el) == -1;
});
temp1=array2.filter(function(el)
{
return arr1.indexOf(el) == -1;
});
newArr=temp.concat(temp1);
return newArr;
}
Similar to above but will work with more than two arrays
var array1 = ['12','1','10','19','100'];
var array2 = ['12','10','19'];
var i = 0;
var hist = {};
var array3 = [];
buildhist(array1);
buildhist(array2);
for (i in hist) {
if (hist[i] === 1) {
array3.push(i);
}
}
console.log(array3);
function buildhist(arr) {
var i;
for (i = arr.length - 1; i >= 0; i--) {
if (hist[arr[i]] === undefined) {
hist[arr[i]] = 0;
}
hist[arr[i]]++;
}
}
