[R] Length problem

[Paolo Grillo]

   Hi all
   I have this problem:
   In my database .dta, called "data" I have five rows
   data<-read.dta("C:\\2_CO_mmobile_ALL_Rid.dta")
   # From this database  I wuold like to create another
   coppie<-c(data[4:length(data)])
   but I find this

   # Length of  original data
   length(data[,4])
   5                       RIGHT!!
   # Length of new data
   length(coppie[1])
   1                      WHY??
   Thank you all for your help
   Paolo Grillo