[R] Basic question on applying a function to each row of a dataframe

Spencer Graves spencer.graves at pdf.com
Sun Jun 8 22:48:04 CEST 2003


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
> 
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