[R] help with paste

[Andrew Criswell]

Hello All:

Suppose the following little data frame:

 > x <- data.frame(dog = c(3,4,6,2,8), cat = c(8,2,3,6,1))
 >
 > x$cat
[1] 8 2 3 6 1
 >

How can I get the paste() function to do the same thing. The command 
below is obviously wrong

 > paste(x, cat, sep = "$")
 >

Thanks,
ANDREW