Use regular expression to return 5 words before and after target word.

[snippsat]

You could do it like this if it's one string and want 5 word before diagnosis and 5 word after.

>>> import re

>>> s1 = 'Hey doctor Who is here - I will add R45.1 as diagnosis, then some other medical terms and stuff about the patient. ffdsas ,dsfd tsdsf'
>>> s2 = 'Some other medical terms and stuff diagnosis of R45.2 was entered for this patient. Where did Doctor Who go? Then xxx feea fdsfd'
>>> r1 = re.search(r"(?:[a-zA-Z'-]+[^a-zA-Z'-]+){0,5}diagnosis(?:[^a-zA-Z'-]+[a-zA-Z'-]+){0,5}", s1)
>>> r2 = re.search(r"(?:[a-zA-Z'-]+[^a-zA-Z'-]+){0,5}diagnosis(?:[^a-zA-Z'-]+[a-zA-Z'-]+){0,5}", s2)
>>> r1.group()
'I will add R45.1 as diagnosis, then some other medical terms'
>>> r2.group()
'other medical terms and stuff diagnosis of R45.2 was entered for'