Newbie string questions

[Matty Sarro]

Hey everyone,
This is a super noob question, so please be gentle.
I am working my way through "Learn Python the Hard Way" using both
python 2.7 and python 3.1 (I want to get a handle on the differences
between the two - the intention to write things in python 3 but be
able to understand things from python 2).

The first quarter or so of the book details lots of stuff about
strings. Most of the learning is by doing, with less of an emphasis on
the theory behind what certain things actually do. The issue is, I
can't seem to find some of the items in the documentation. Right now
what is stumping me... what exactly does %r do? I can't find it in the
documentation anywhere.
-Matty