title: Creating comma-separated string from list
body: <p>I have a list of ints and want to create a comma-separated string. The following:</p>
  
  <pre><code>x = [3, 1, 4, 1, 5]
  y = ",".join(x)
  </code></pre>
  
  <p>Give the error:</p>
  
  <pre><code>TypeError: sequence item 0: expected string, int found
  </code></pre>
  
  <p>How do I create the string? I could manually convert every element from int to string, insert this into a new list, and then do the join on this new list, but I'm wondering if there is a cleaner solution.</p>