Transpose a length and filter to just a foldr

Question

I have this function :

count :: Int -> [(Float,Int)] -> Int
count n p = length $ filter ((==n).snd) p

and I want to transpose it to a foldr but im having troubles with the lambda function

Answer 1

Try this:

count n = foldr (\(f,i) j -> if (i==n) then j+1 else j) 0