R script to enumerate all binary strings of a certain length and type. Useful for getting all possible combinations of columns, for example.

enumerate_bin.R

# "enumerate_bin("1xx000") generates a vector of all binary strings: c("100000","101000","110000","111000")
enumerate_bin <- function(input_str) {
	strlen<-nchar(input_str)
	for(i in 1:strlen) {
		if(tolower(substr(input_str,i,i))=="x") {
			str0 <- paste(substr(input_str,1,i-1),"0",substr(input_str,i+1,strlen),sep="")
			str1 <- paste(substr(input_str,1,i-1),"1",substr(input_str,i+1,strlen),sep="")
			return(c(enumerate_bin(str0), enumerate_bin(str1)))
		}
	}
	return(input_str)
}