<p>Apparently xrange is faster but I have no idea why it's faster (and no proof besides the anecdotal so far that it is faster) or what besides that is different about</p>

<pre><code>for i in range(0, 20):
for i in xrange(0, 20):
</code></pre>

See this
post
to find difference between range and xrange:
To quote:
```
range
```
returns exactly what you think: a list of consecutive
  integers, of a defined length beginning with 0.
```
xrange
```
, however,
  returns an
"xrange object"
, which acts a great deal like an iterator