refer to range of columns by name in R

Question

I need help with something that might be fairly simple in R. I want to refer to a range of columns in a data frame (e.g., extracting a few select variables). However, I don\

Answer 1

Here is a fun little function that combines the ideas behind Largh's answer with a handy function call. To use it, just enter

call.cols(mydata, "firstvarname", "lastvarname")

call.cols <- function(df, startvar, endvar) {
  col.num <- function(df){
    var.nums <- seq(1,ncol(df))
    names(var.nums) <- colnames(df)      
    return(var.nums)
  } 

 start.num <- as.numeric(col.num(df)[startvar])
 end.num <- as.numeric(col.num(df)[endvar])
 range.num <- start.num:end.num
 return(df[range.num]) 
}

I plan to expand this to use for scale creation for psychometric research.