Question

I would like to determine whether a string S has a substring MYSUBSTRING preceded by two consecutive digits I need to determine.

For example:

‘aaa79bbbMYSUBSTRINGccc’
==> I want 7, 9 and True (or 7, 9 and MYSUBSTRING)

‘aaa79bbbccc’
==> I want 7, 9 and False (or 7, 9 and None)

Can I do that with a SINGLE regex? If so, which one?

Answer 1

The following regex should do it:

(\d)(\d)(?:.*?(MYSUBSTRING))?

>>> re.search(r'(\d)(\d)(?:.*?(MYSUBSTRING))?', 'aaa79bbbMYSUBSTRINGccc').groups()
('7', '9', 'MYSUBSTRING')
>>> re.search(r'(\d)(\d)(?:.*?(MYSUBSTRING))?', 'aaa79bbbccc').groups()
('7', '9', None)