Index of current element in Haskell list comprehension

Question

Is there any way that I can know the index of current element that x is pointing to in the code below:

funcName k = [<current_index_here> | x <- list, x == k]

Any help would be greatly appreciated.. Thanks :)

Answer 1

Index each element with an integer using zip:

funcName k = [if i == 2 then ... else ... | (i,x) <- zip [0..] list, x == k]

Answer 2

Maybe like this with the ilist library (a very useful library):

import Data.List.Index 
> indexed [i*i | i <- [7,6,5]]
[(0,49),(1,36),(2,25)]

Not sure it's exactly what you want but that should be close I believe.