>>> r = "name: srek age :24 description: blah blah"
>>> import re
>>> regex = re.compile(r"\b(\w+)\s*:\s*([^:]*)(?=\s+\w+\s*:|$)")
>>> d = dict(regex.findall(r))
>>> d
{'age': '24', 'name': 'srek', 'description': 'blah blah'}
Explanation:
\b # Start at a word boundary
(\w+) # Match and capture a single word (1+ alnum characters)
\s*:\s* # Match a colon, optionally surrounded by whitespace
([^:]*) # Match any number of non-colon characters
(?= # Make sure that we stop when the following can be matched:
\s+\w+\s*: # the next dictionary key
| # or
$ # the end of the string
) # End of lookahead