You're right, I meant (!!).  I've been playing with Array values recently, and (!) is used there.

As has already been stated, genericIndex in the Data.List module will help with the Integer problem, as will fromInteger.

As has also already been mentioned, lists + indexing = slow.  If you care about efficiency, and you need indexing, you might want to look into Data.Array.IArray if you have fixed bounds or Data.Sequence if you don't.

On Fri, Sep 10, 2010 at 11:12 AM, Lorenzo Isella <lorenzo.isella@gmail.com> wrote:
On 09/10/2010 05:03 PM, Alex Rozenshteyn wrote:

alternatively (and more cleanly),
 > results = map (ml !) sel

Thanks Alex. I am left with this problem only: the entries of sel are (in my code) Integer rather than Int so...I get an error message when compiling sine "!!" (I believe you left out a "!") expects an Int instead of an Integer.
Any idea about how to fix this without converting sel from Integer to Int?
Many thanks

Lorenzo



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          Alex R