Using different function (parameters) with apply
On 18-04-2013, at 07:20, Sachinthaka Abeywardana <sachin.abeywardana at gmail.com> wrote:
Hi All,
I have the following problem (read the commented bit below):
a<-matrix(1:9,nrow=3)
a
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
div<-1:3
apply(a,2,function(x)x/div) ##want to divide each column by div-
instead each row is divided##
[,1] [,2] [,3]
[1,] 1 4.0 7
[2,] 1 2.5 4
[3,] 1 2.0 3
column 1 is c(1,2,3) and divided by your vector div gives the first column c(1/1,2/2,3/3) = c(1,1,1) and that is correct. column 3 is c(7,8,9) and divided by vector div gives c(7/1, 8/2 , 9/3) = c(7,4,3). Also correct.
apply(a,1,function(x)x/div) ##Changing Margin from 2 to 1 does something completele weird## [,1] [,2] [,3] [1,] 1.000000 2.000000 3 [2,] 2.000000 2.500000 3 [3,] 2.333333 2.666667 3
You are dividing each row by vector div). The result for row 1 is the first column and so forth. Probably if you did t(?) you would get what you want/expect.
Any thoughts?
Your conclusions are incorrect. What is the result that you want (or expect)? Berend