Question

I have several array to deal with. I need to extract the most duplicate value from each array.

From [3, 7, 7, 7], I need to find the value 7. Each array size is 4. For now, I don’t have to think about when the most duplicate values are more than one such as [3, 7, 7, 7]. All the values are a number.

I looked around the web. I found several ways to make an array to become uniq(). But I haven’t found a way to get the duplicate value. I am using jQuery, but raw JavaScript is fine for this task.

Answer 1

Not perfect in terms of efficiency, but does the job:

var nums = [3, 7, 7, 7];
var freqs = {};
var max_index;
var max_value = -1/0; // Negative infinity.

$.each(nums, function(i, v) {
  if (freqs[v] != undefined) {
    freqs[v]++;
  } else {
    freqs[v] = 1;
  }
});
$.each(freqs, function(num, freq) {
  if (freq > max_value) {
    max_value = freq;
    max_index = num;
  }
});

if (max_index != undefined) {
  alert("Most common element is " + max_index + " with " + max_value + " repetition(s).");
}
​