if you mean Condition List, I believe that the string variable can be used to hold the correct button name for each condition.
The Button element returns a name of a pressed button via the "Triggering Button" property. If you set a proxy variable to it, then you can evaluate an answer by code, e.g.
The button names for arrows (in the latest EventIDE versions) are Left and Right or NumberPad4 and NumberPad6 (for the pad buttons). Note that you need to keep the same letter casing, when you enter the button names in Condition List.