Regular expression to find digit in a string

>>> import re

>>> re.findall(r'\d+', 'hello 42 I\'m a 32 string 30')
['42', '32', '30']

If you only want numbers delimited by word boundaries (space, period, comma), you can use \b :

>>> re.findall(r'\b\d+\b', 'he33llo 42 I\'m a 32 string 30')
['42', '32', '30']