title: Is there a measure to find the distance between different sized, unsorted arrays of numbers?
body: <p>Say I have a arrays of numbers, such as [2,6,3,4]. I would like a way to quantify the distance between this array and other arrays. Some sort of similarity measure that behaves according to the following rules:</p>
  
  <ol>
  <li>The order of the elements in the array shouldn't matter. So the distance between [2,6,3,4] and [2,3,4,6] should be ideally zero.</li>
  <li>The array can be of different sizes. So I'd like a similarity measure between array such as [2,6,3,4] and [2,6,3,4,6], or [2,6,3,4] and [2,4].</li>
  <li>It should have some resistance to outliers. For example, [1,2,3] should be similar to [1,2,3,100]</li>
  </ol>
  
  <p>Is there any method that does something similar to this? Thanks in advance.</p>