title: convert list elements into list of tuples
body: <pre><code>header =  ['chr', 'pos', 'ms01e_PI', 'ms01e_PG_al', 'ms02g_PI', 'ms02g_PG_al', 'ms03g_PI', 'ms03g_PG_al', 'ms04h_PI', 'ms04h_PG_al']
  </code></pre>
  
  <p>I want to convert the above list elements into list of tuples. Like:</p>
  
  <pre><code>sample_list = [('ms01e_PI', 'ms01e_PG_al'), ('ms02g_PI', 'ms02g_PG_al'),
                'ms03g_PI', 'ms03g_PG_al'), ('ms04h_PI', 'ms04h_PG_al')]
  </code></pre>
  
  <p>I am thinking lambda or list comprehension can be used to approach this in a short and comprehensive way.</p>
  
  <pre><code>sample_list = [lambda (x,y): x = a if '_PI' in a for a in header ..]
  </code></pre>
  
  <p>or, </p>
  
  <pre><code>[(x, y) if '_PI' and '_PG_al' in a for a in header]
  </code></pre>
  
  <p>any suggestions?</p>