You can extract all numbers from a string using REGEX expression - \d+
Sample:
data:vat type string value '12asdf34ABwerr1234'.
data:results_tab type match_result_tab.
find all occurrences of regex '\d+' in vat
results results_tab.
loop at results_tab into data(result).
write: / vat+result-offset(result-length).
endloop.
This will extract all the numbers from the string and display output as:
12
34
1234
Once you have the numbers separated from both strings, you should be able to compare them and find the match.
Thanks,
Juwin