Where is the join function?

Question

I need a join function to add separators between list members. I found this function in Data.List.Utils and Data.String.Utils. Unfortunately, these modules do not seem to be part of the standard platform.
Since this is a fairly standard feature, I'm sure it should be somewhere on a standard platform, possibly with a different name.

Any idea?

Update

I found a solution (but can not accept my answer, I have to wait 2 days ???)

Answer 1

I found it (thanks Hoogle), it's called intercalate.

Answer 2

Data.List intersperse, a -> [a] -> [a] intercalate, [a] -> [[a]] -> [a]

:
intersperse '_' "foo" "f_o_o"
intercalate "baa" ["f", "o", "o"] "fbaaobaaobaa"