Finding items that appear only one time in a Javascript array

Question

I\'m trying to find the items that appear only one time in a Javascript array. In the following array:

[\'txfa2\',\'txfa9\',\'txfa2\',\'txfa1\',\'txfa3\',\'t         


        

Answer 1

a simple approach will be making advantage of Javascript's builtin object. Let an object act as a counter for each item in the collection, then iterate over it to check which item has a counter of 1.

it's quite fast;

var items = ['txfa2', 'txfa9', 'txfa2', 'txfa1', 'txfa3', 'txfa4', 'txfa8', 'txfa9', 'txfa2', 'txfa8'],
  result = [],
  i, 
  k, 
  container = {};

for (i = 0; i < items.length; ++i) {
  if (items[i] in container) {
    container[items[i]]++;
  } else {
    container[items[i]] = 1;
  }
}

for (k in container) {
  if (container[k] == 1) {
    result.push(k);
  }
}

console.log(result)