Given a list,
x:("A","B","C","D")
There are several ways we could find the index of a specific element.
Building a dictionary:
(x dict keys x)["C"]
Querying:
first extract index where value="C" from x
Arithmetic:
sum (keys x) * x="C"
Variants of these methods can also be used to search for several items in parallel:
(x dict keys x) @ "C","A" # (2,0) extract index where value in "C","A" from x # (0,2) extract index where value="C" from "ABCBABBCC" # (2,7,8)
If you're ever specifically searching within strings, consider rtext.find[] (which can optionally ignore case, too).
first @ rtext.find["ALPHABETICAL APPLES" "A"] # (0,4,10,13)