On Feb 2, 2011, at 9:12 AM, ADias wrote:
Hi
I have this function and this matrix:
function(x,y) x+y/x
m<-matrix(c(1,2,4,2,10,8),3,2)
m
[,1] [,2]
[1,] 1 2
[2,] 2 10
[3,] 4 8
each row represent a point (x,y) in a chart and I want via my
fucntion to
calculate the image in order to get this results:
for point (1,2) I would get 1+2/1 = 3
for point (2,10) I would get 2+10/2 = 7
for point (4,8) I would get 4+8/4 = 6
I have tried using sapply here but I get this:
sapply(m,function(x,y) x+y/x)
Error in y/x : 'y' is missing
I'm not sure what sapply does with a matrix argument. I've only used t
with vectors and lists. I suspect that it would straighten out the
argument to a length = 6 vector. (And then, of course, the "y"
wouldn't be there.)
what I am doing wrong?
Two things: instead use apply() and realize that the argument is
passed as a vector
apply(m, 1, function(x) x[1] +x[2]/x[1] )
--
David Winsemius, MD
West Hartford, CT
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