title: Splitting string into groups of specific length
body: <p>I was wondering what the best way to split up a string such as <code>"abcdefghijklmnopqrstuvwxyz"</code> into a list of groups of 2 (splitting the string into: <code>["ab", "bc", "cd", ... "yz]</code>) is in Python.</p>
  
  <p>Or what about in groups of 3: splitting the string into <code>["abc", "bcd", "cde", ... "xyz"]</code></p>
  
  <p>Thanks!</p>