Automatically generate variable names from Pattern, R

genVarNames.R

#// Say you were building a dataset and wanted to automatically 
#// generate variable names by some pattern.
#// For instance, you might want to do this with population counts
#// within 100 census tracts by race
#// IE: 
#
#   tracts <- paste("c", rep(1:100), sep="")
#   race - c("black", "white", "hispanic")
#
#// In this case you would want to generate 300 unique variable names

#// This function will generate these variable names automatically 
#	 when provided with:
#
#   1. the "roots" - in the example above, the unique census tracts
#   2. the "vars" - in the example above, the unique races

#// see below for the example: 

tracts <- paste("c", rep(1:100), sep="")
races <- c("blk", "wht", "hsp")

genVarNames <- function(roots, vars, delim="_"){ #delim can also be defined as "." or ""
	n.roots <- length(roots)
	n.vars <- length(vars)
	tot.vars <- n.roots*n.vars
	instances <- seq(0,tot.vars, by=n.vars) + 1
	varnames <- character(tot.vars)
		
               for (i in instances){
			range <- (i+(n.vars-1))
			j <- range/n.vars
			varnames[i:range]<- paste(roots[j], delim, vars[1:n.vars], sep="")
		}
		varnames <- varnames[-c((length(varnames)-(n.vars-1)):length(varnames))]
		return(varnames)
}

genVarNames(tracts, races)