Basic question on applying a function to each row of a dataframe

From: Spencer Graves <spencer.graves at PDF.COM>
To: peter leonard <pfleonard at hotmail.com>
CC: r-help at stat.math.ethz.ch
Subject: Re: [R] Basic question on applying a function to each row of 
a	dataframe
Date: Sun, 08 Jun 2003 13:48:04 -0700

How about the following:

DF <- data.frame(x=1:4, y=rep(1,4))
foo <- function(x, y)x+y
foo(DF$x, DF$y)

[1] 2 3 4 5

hth.  spencer graves

peter leonard wrote:

Hi,

I have a function foo(x,y) and a dataframe, DF,  comprised of two vectors, 
x & w,  as follows :

  x w
1  1 1
2  2 1
3  3 1
4  4 1

etc


I would like to apply the function foo to each 'pair' within DF e.g  
foo(1,1), foo(2,1), foo(3,1) etc

I have tried

apply(DF,foo)
apply(DF[,],foo)
apply(DF[DF$x,DF$w],foo)

However, none of the above worked. Can anyone help ?

Thanks in advance,
Peter