title: Python: reduce (list of strings) -> string
body: <pre><code>&gt;&gt;&gt; import functools as ft
  &gt;&gt;&gt; bk = ft.reduce(lambda x, y: x[0] + "." + y[0], ['alfa', 'bravo', 'charlie', 'delta'])
  &gt;&gt;&gt; bk
  'a.d'
  &gt;&gt;&gt; km = ft.reduce(lambda x, y: x + y, [1, 2, 3, 4])
  &gt;&gt;&gt; km
  10
  &gt;&gt;&gt; bk = ft.reduce(lambda x, y: x[0] + y[0], ['alfa', 'bravo', 'charlie', 'delta'])
  &gt;&gt;&gt; bk
  'ad'
  &gt;&gt;&gt;
  </code></pre>
  
  <p>I expected something like 'a.b.c.d' or 'abcd'. Somehow, can't explain the results. There are similar questions here, but not quite like this one.</p>