[R] How to mean, min lists and numbers

David Winsemius dwinsemius at comcast.net
Mon Jul 12 17:20:51 CEST 2010

On Jul 12, 2010, at 11:10 AM, guox at ucalgary.ca wrote:

> I would like to sum/mean/min a list of lists and numbers to return the
> related lists.

You will advance in your understanding faster if you adopt the correct  
> -1+2*c(1,1,0)+2+c(-1,10,-1) returns c(2,13,0) but

... which is NOT a list, it is a vector.

> sum(1,2*c(1,1,0),2,c(-1,10,-1)) returns 15 not a list.
> Using the suggestions of Gabor Grothendieck,
> Reduce('+',list(-1,2*c(1,1,0),2,c(-1,10,-1))) returns what we want,
> c(2,13,0).
> However, it seems that this way does not work to mean/min.

If you want a running cumulative mean of a vector, i.e,  
c( mean(vec[1]), mean(vec[1:2]), ,,, mean(vec) ):

vec <- sample(1:20)

sapply(1:length(vec), function(x) mean(vec[1:x])

> So, how to mean/min a list of lists and numbers to return a list?

Not a list and not working on "a list of lists". A vector.

David Winsemius, MD
West Hartford, CT

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