You can use regular expressions with Xpath, if you use the matches Xpath function. This expression checks the variable, MyVariable:
matches($MyVariable, "^(DIN|ISO) A[3-5]$")
The regular expression above tests, if the variable:
•starts with either 'DIN' or 'ISO'
•then a space and the letter 'A'
•finish with 3, 4 or 5
You can use the expression in IF- and select elements to let the output depend on the result of a test.
Remember, that you can combine the XPath functions, and that there are many other functions not mentioned here. This appendix hopefully gives you an idea of how strong a tool this is. You can e.g. refer to this link for additional information: https://www.w3schools.com/js/js_regexp.asp