Python re.findall() is not working as expected

Question

I have the code:

import re
sequence=\"aabbaa\"
rexp=re.compile(\"(aa|bb)+\")
rexp.findall(sequence)

This returns [\'aa\']

Answer 1

your pattern

rexp=re.compile("(aa|bb)+")

matches the whole string aabbaa. to clarify just look at this

>>> re.match(re.compile("(aa|bb)+"),"aabbaa").group(0)
'aabbaa'

Also no other substrings are to match then

>>> re.match(re.compile("(aa|bb)+"),"aabbaa").group(1)
'aa'

so a findall will return the one substring only

>>> re.findall(re.compile("(aa|bb)+"),"aabbaa")
['aa']
>>>