Hello, I can't say I have every used the regex option in application modeller, but I have used it for string text parsing/extraction. I can recommend this website as an experimentation area to figure out your expressions:
https://regexr.com/
Also, the Blue Prism product help contains the following information:
Regular Expressions
Blue Prism uses the Microsoft .NET Regular Expression classes. The following table lists some of the meta-characters most commonly used in Regular Expression searches. For comprehensive information about regular expressions and the full range of options available, see the .NET Framework Regular Expressions and Regular Expression Language Elements topics references on the Microsoft MSDN website.
Character
Description
*
Matches the preceding character or sub-expression zero or more times. For example, zo* matches ""z"" and ""zoo"". * is equivalent to {0,}.
+
Matches the preceding character or sub-expression one or more times. For example, 'zo+' matches ""zo"" and ""zoo"", but not ""z"". + is equivalent to {1,}.
?
Matches the preceding character or sub-expression zero or one time. For example, ""do(es)?"" matches the ""do"" in ""do"" or ""does"". ? is equivalent to {0,1}
{n}
n is a non-negative integer. Matches exactly n times. For example, 'o{2}' does not match the ""o"" in ""Bob,"" but it does match the double-instance of ""o"" in ""food"".
.
Matches any single character except ""\n"". To match any character including the '\n', use a pattern such as '[\s\S].
