title: Removing value from array if it is contained by another array
body: <p>I have two arrays</p>
  
  <pre><code>main_array = [[0,[1,4,5]], [1,[4,6,8]], [2,[5,6,7,8]], [3,[9,8]], [4,[7,2]]]
  other_array = [[1,4,5],[9,8]]
  </code></pre>
  
  <p>What I want to do is to delete those elements in <code>main_array</code> if it can be found in <code>other_array</code>. (Meaning I will be left with <code>[[1,[4,6,8]], [2,[5,6,7,8]],[4,[7,2]]]</code> ) So I did the following:</p>
  
  <pre><code>other_array.each { |x|
  for i in 0..main_array.length-1
    main_array.delete(x)
  }
  </code></pre>
  
  <p>It didn't work. Any clues on how I should approach this?</p>