regex to find a string or another string in search and then return one part of the searched with group

I have a string which is a file name, examples:

'20220213-0000-FSC-814-SC_VIRG_REFBAL_PRES_NPMINMAX-v1.xml'
'20220213-0000-F814-SC_VIRG_REFBAL_PRES_NPMINMAX-v1.xml'

I want to find a string with re.search which corresponds to Fddd or FSC-ddd.

I have a regex like this:

type_match = re.search(r'(F(d{3}))|(FSC-(d{3}))', string)

Later after I have found for example FSC-814 , I want to get only the number from this found string, I used:

int(type_match.group(1))

but it does not work after I included or statement in the re.search

Answer

You can use

F(?:SC)?-?(d{3})

See the regex demo.

Details:

• F – an F char
• (?:SC)? – an optional SC char sequence
• -? – an optional hyphen
• (d{3}) – Capturing group 1: three digits.

See the Python demo:

import re
texts = ['20220213-0000-FSC-814-SC_VIRG_REFBAL_PRES_NPMINMAX-v1.xml',
'20220213-0000-F814-SC_VIRG_REFBAL_PRES_NPMINMAX-v1.xml']
pattern = r'F(?:SC)?-?(d{3})'
for text in texts:
    match = re.search(pattern, text)
    if match:
        print (match.group(1))

Output:

814
814