# 99 questions/Solutions/16

From HaskellWiki

< 99 questions | Solutions

(**) Drop every N'th element from a list.

```
dropEvery :: [a] -> Int -> [a]
dropEvery [] _ = []
dropEvery (x:xs) n = dropEvery' (x:xs) n 1 where
dropEvery' (x:xs) n i = (if (n `divides` i) then
[] else
[x])
++ (dropEvery' xs n (i+1))
dropEvery' [] _ _ = []
divides x y = y `mod` x == 0
```

An alternative iterative solution:

```
dropEvery :: [a] -> Int -> [a]
dropEvery list count = helper list count count
where helper [] _ _ = []
helper (x:xs) count 1 = helper xs count count
helper (x:xs) count n = x : (helper xs count (n - 1))
```

Yet another iterative solution which divides lists using Prelude:

```
dropEvery :: [a] -> Int -> [a]
dropEvery [] _ = []
dropEvery list count = (take (count-1) list) ++ dropEvery (drop count list) count
```

A similar approach using guards:

```
dropEvery :: [a] -> Int -> [a]
dropEvery xs n
| length xs < n = xs
| otherwise = take (n-1) xs ++ dropEvery (drop n xs) n
```

Using zip:

```
dropEvery n = map snd . filter ((n/=) . fst) . zip (cycle [1..n])
```