Recursion over lists

Philippa Cowderoy flippa at
Mon Feb 18 10:39:16 EST 2008

On Mon, 18 Feb 2008, TOPE KAREM wrote:

> Hello everyone,
> I am just learning to program in Haskell, and I found recursion very
> interesting.
> However, I need to write a recursive function over two lists.
> The function must  check the  elements in the  two lists and  return an
> element that is common to both lists if there is any.
> Any assistance would be appreciated.

Imagine for a moment that instead of "two lists" you have "a pair of 
lists", and thus each time you recurse you must generate a new pair of 
lists. After that it should be more or less business as usual if you're 
comfortable working on one list.

flippa at

There is no magic bullet. There are, however, plenty of bullets that
magically home in on feet when not used in exactly the right circumstances.

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