Append number to a comma separated list

Question

the list looks like:

3434,346,1,6,46

How can I append a number to it with javascript, but only if it doesn't already exist in it?

Answer 1

Assuming your initial value is a string (you didn't say).

var listOfNumbers = '3434,346,1,6,46', add = 34332;
var numbers = listOfNumbers.split(',');
if(numbers.indexOf(add)!=-1) {
  numbers.push(add);
}
listOfNumbers = numbers.join(',');

Basically i convert the string into an array, check the existence of the value using indexOf(), adding only if it doesn't exist.

I then convert the value back to a string using join.

Answer 2

If that is a string, you can use the .split() and .join() functions, as well as .push():

var data = '3434,346,1,6,46';
var arr = data.split(',');

var add = newInt;
arr.push(newInt);
data = arr.join(',');

If that is already an array, you can just use .push():

var data = [3434,346,1,6,46];
var add = newInt;

data.push(add);

UPDATE: Didn't read the last line to check for duplicates, the best approach I can think of is a loop:

var data = [3434,346,1,6,46];
var add = newInt;

var exists = false;
for (var i = 0; i < input.length; i++) {
    if (data[i] == add) {
        exists = true;
        break;
    }
}

if (!exists) {
    data.push(add);

    // then you would join if you wanted a string
}