VBS Regex getting the underscore from a string

Question

I have a simple outcome to detect part of a file name. My files have their general name (FILENAME), a second name (SECONDNAME#) and a final tag, all links by underscores.

I am after the second name, which can have a small number of values. The third part, the final tag, can be highly variable and is not checked for.

FILENAME_SECONDNAME1_DS.txt

FILENAME_SECONDNAME2_DS.txt

FILENAME_SECONDNAME3_ER.txt

Detecting the trailing underscore after teh second name is important to help indicate I have the second name and are not accidentally detecting a similar string part in the filename.

I check with the following

set RE = new RegExp
RE.Ignorecase = true

sCONST = "FILENAME_SECONDNAME1_DS.txt"

RE.pattern = "(SECONDNAME1)|(SECONDNAME2)|(SECONDNAME3)_"
if RE.test(sCONST) = true then
    set matches = RE.Execute(sCONST)
    for each match in matches
        MsgBox match.Value
    next
end if

VB's RegExp matches my pattern but match.Value never has the underscore. I can only assume I am not matching the underscore with my pattern. How can I get the underscore included in my matches?

Answer 1

The pipe works on the whole thing, so with your current regex, the 3 possible alternatives are SECONDNAME1, SECONDNAME2, and SECONDNAME3_.

That being said, you don't even need the pipe operator in this case.

Do the following instead:

SECONDNAME[1-3]_

Just match SECONDNAME followed by either 1, 2, or 3, which is then followed by an underscore.

Demo