title: How to split list element into two?
body: <p>If I have data stored in a list, e.g.</p>
  
  <pre><code>images = ['pdf-one','gif-two','jpg-three']
  </code></pre>
  
  <p>How do I split these into multiple elements at the hyphen - not sublists. I.e.</p>
  
  <pre><code>images = ['pdf','-one','gif','-two','jpg','-three']
  </code></pre>
  
  <p>not</p>
  
  <pre><code>images = [['pdf','-one'],['gif','-two'],['jpg','-three']]
  </code></pre>