Drop every nth item revised

A friendly Clojurian has pointed out that I gave up too soon on my first attempt to create a function that drops every nth element from a sequence.

If you start with a sequence:-

user=> (def s (range 1 20))
#'user/s
user=> s
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19)

You can break this into sections where all except the last one have n elements and the final one has up to n elements depending on how many are left: this is the function partition-all:-

user=> (partition-all 4 s)
((1 2 3 4) (5 6 7 8) (9 10 11 12) (13 14 15 16) (17 18 19))
user=> (partition-all 5 s)
((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14 15) (16 17 18 19))
user=> (partition-all 6 s)
((1 2 3 4 5 6) (7 8 9 10 11 12) (13 14 15 16 17 18) (19))

This is different from function partition, which would silently omit the final elements if there were not enough to make another batch of n.

So now I can take only n-1 elements from each batch, there's a function drop-last which does this:

user=> (map drop-last (partition-all 6 s))
((1 2 3 4 5) (7 8 9 10 11) (13 14 15 16 17) (19))

So the final element from each batch of 6 goes.  Then flatten the batches to make a single sequence:-

user=> (flatten (map drop-last (partition-all 6 s)))
(1 2 3 4 5 7 8 9 10 11 13 14 15 16 17 19)

There we are, each 6th element dropped.  Far more functional than the solution that works through the list.

Therefore the function to drop every nth item from a sequence looks like this:

(defn drop-nth [n s]
  (flatten (map drop-last (partition-all n s))))

Isn't that honey?