[R] does R have a command the same with Stata's loop command: ` '

[Hey Sky]

hey, Rers

in Stata therer is a loop command ` ' which could do the following:

forvalue i=1/10 {
 gen x`i'=expression
}

this will generate variable: x1,x2,,,,,x10. so, does R have a corresponding one 
to this?


And one more very basic question: after I open a file and modify it, such as 
generate some new variables and change some old ones, how to use the changed 
dataset in analysis, except the method save and reload it? 


I have tried but did not get the right thing done:
mydata<-read(flie=".....")
........
detach()
attach(names of my data set)


any answer are appreciated.

Nan
from Montreal