[racket] How to iterate through the arrays in a matrix?

Hi,
I have a 80 X 4 matrix. I have iterate through each row and subtract each
row with another array at each iteration. At first I thought to convert all
array to list and do all the operations and then again convert the final
list if lists to a matrix. But I somehow think that is not a suited way. I
tried using "for*/matrix" but could not get it right. Could any one give an
example on how to iterate a matrix (array for arrays)?

My matrix looks like this:
> (list*->matrix final-data)
(array
 #[#[5.1 3.5 1.4 0.2]
   #[4.9 3.0 1.4 0.2]
   #[4.7 3.2 1.3 0.2]
   #[4.6 3.1 1.5 0.2]
   #[5.0 3.6 1.4 0.2]
   #[5.4 3.9 1.7 0.4]
   #[4.6 3.4 1.4 0.3]
   #[5.0 3.4 1.5 0.2]
   #[4.4 2.9 1.4 0.2]
   #[4.9 3.1 1.5 0.1]
...........

Thanks!
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.racket-lang.org/users/archive/attachments/20141128/4706a107/attachment.html>