title: F# Compare two lists, take different actions
body: <p>How to idiomatically do this: given a list of stuff, find if an item in it meets a criteria in another list, if it does do one action, if it doesn't do another action. I saw code doing this in C# and I wondered how I would do it in F#. </p>
  
  <p>Here is the code as it would be implemented imperatively in F#:</p>
  
  <pre><code>let find list1 list2 =
      for i in list1 do
          let mutable found = false
          for k in list2 do
              if i=k then    //if the criteria is equals
                  found &lt;- true
                  //do task using k &amp; i
          if found =false then   
              //do other task using i
              ()
  </code></pre>
  
  <p>How can this be done more functionally?</p>