Boolean function

Is there any way of determining if a string contains a certain sequence of characters? I would like to use a boolean function similar to contain(string, charSequence) in a $if(x,y,z) function [if x is true, y is returned, otherwise z].

Thanks.

You can find what you search there
https://docs.mp3tag.de/scripting

DD.20090805.0535.CEST