title: scala Remove (in place) all elements of a ListBuffer that meet a condition
body: <p>I have a ListBuffer. I want to remove all elements that meet a certain condition.</p>
  
  <p>I could iterate over it and remove each element. But what doe Scala say about mutating a list that you are iterating over? Will it work, or will it delete the wrong elements/not return all elements? (A quick attempt with the REPL suggests that yes, it will mess up)</p>
  
  <p>I could repeatedly call find and then remove the found element until I don't find any more, but that sounds inefficient.</p>
  
  <p>.filter will return me a new ListBuffer without the elements, but I want to do it in place.</p>
  
  <p>This</p>
  
  <pre><code>def --= (xs: TraversableOnce[A]) : ListBuffer.this.type
  Removes all elements produced by an iterator from this list buffer.
  </code></pre>
  
  <p>looks promising but I can't quite see how to use it here</p>
  
  <p>How should I do this?</p>