Find the position from a string in a substring in a sentence-CodePudding

I have the sentence : Take 1 tablet in the morning and at noon for **1** week

I try to find the position of the 1 element corresponding to the 1 for 1 week

But if i use re.search for the '1' element in my sentence i've got the 1 position from the 1 element corresponding to 1 tablet

Thanks to NLP I can extract the element for 1 week. So i would like to find the 1 element in the substring for 1 week in the sentence.

CodePudding user response：

You can find the span of for 1 week and the span of 1 within for 1 week (this is quite trivial in this example but would be more interesting with a more complex regex):

s = 'Take 1 tablet in the morning and at noon for 1 week'

import re
m = re.search('for 1 week', s)
start, stop = m.span()
m2 = re.search('1', m.group())
start2, stop2 = m2.span()
start start2

output:

>>> start start2
45

>>> s[45]
'1'

slightly more complex example:

m = re.search('(for|during) \d  (week|day|month)', s)
start, stop = m.span()
m2 = re.search('\d ', m.group())
start2, stop2 = m2.span()
print(f'position {start start2}: {s[start start2]}')

output: position 45: 1