Hi,

Ah! Thanks for your help! I have even seen Reduce before but for some reason just didn't make the connection. This helps a ton! Thanks again.

Kind regards,
Greg
On Oct 29, 2010, at 6:53 PM, Jorge Ivan Velez wrote:

> Hi Greg,
> 
> Here are two ways of doing it:
> 
> > mylist <- list(x = rpois(10, 10), y = rpois(10, 20), z = rpois(10, 5))
> > mylist
> $x
>  [1]  3 13 14 16 10  7  3  5 12 14
> 
> $y
>  [1] 17 16 26 13 23 24 16 28 23 12
> 
> $z
>  [1]  2  6  5  5  5  1  9 11  6  4
> 
> > 
> > colMeans(do.call(rbind, mylist), na.rm = TRUE)
>  [1]  7.333333 11.666667 15.000000 11.333333 12.666667 10.666667  9.333333 14.666667 13.666667
> [10] 10.000000
> > 
> > Reduce("+", mylist)/length(mylist)
>  [1]  7.333333 11.666667 15.000000 11.333333 12.666667 10.666667  9.333333 14.666667 13.666667
> [10] 10.000000
> 
> 
> HTH,
> Jorge
> 
> 
> On Fri, Oct 29, 2010 at 6:46 PM, Gregory Ryslik <> wrote:
> Hi Everyone,
> 
> I have a list of vectors like this (in this case it's 3 vectors but assume the vector count and the length of each vector is not known):
> 
> [[1]]
> [1]  9  5  7  2 14  4  4  3
> 
> [[2]]
> [1]  3  6 25  2 14  3  3  4
> 
> [[3]]
> [1] 28  4 14  3 14  2  4  5
> 
> What I want to do is take the average vertically. Thus I want to do 9+3+28 /3, 5+6+4 /3, etc... and then have it return a vector. I'm assuming that if I can sum it, I can count it to so summing this would be just as helpful.
> 
> I understand I can first go through each element of the list, get a vector, cbind into  matrix and sum across but I was hoping to avoid that... I tried getting it to work with mapply but am having difficulties...
> 
> Thanks!
> 
> Kind regards,
> Greg
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