Question

I am trying out the example given in http://docs.python.org/library/re.html for the group numbering and matching. Very simply, (.+) \1 should match two pieces of identical text separated by a space, and it lists the the as an example. However,

 re.search('(.+) \1','the the')

returns a None.

I am using re version 2.2.1.

Answer 1

You either need to escape your escapes or use raw strings.
e.g.

re.search('(.+) \\1', 'the the' )

or

re.search(r'(.+) \1', 'the the' )

see the Raw String Notation section on the same page as the example.