Returns the index of the specified list item
(vl-position symbol list)
Arguments
Any AutoLISP symbol.
A true list.
Return Values
An integer containing the index position of symbol in list; otherwise nil if symbol does not exist in the list.
Note that the first list element is index 0, the second element is index 1, and so on.
Examples
_$ (setq stuff (list "a" "b" "c" "d" "e"))
("a" "b" "c" "d" "e")
_$ (vl-position "c" stuff)
2