[R] Using apply for two datasets

[Christos Argyropoulos]

It depends on how the data are arranged

##----------------------------------------------------
x<-matrix(c(1,2,3,2,8,2,4,5,6),nrow=3)
y<-matrix(c(10,2,13,0,8,4,4.2,5.2,6.2),nrow=3)

q<-mapply(t.test,as.data.frame(x),as.data.frame(y))

q

## The ith column of q contain the results of applying t.test to 
## the ith column of x and the jth column of y
##----------------------------------------------------

Since the t.test returns a list, you can wrap it in your own function if 
you want to process the data in an assembly line fashion.

Continuing the previous example:

my.t<-function(x,y,...) { c(t.test(x,y,...))[1:3] }

q2<-mapply(my.t,as.data.frame(x),as.data.frame(y))

q2


Good luck!

Christos Argyropoulos
University of Pittsburgh Medical Center