R/extract.R

In eloch216/EdR: Ed's Handy Functions

EdR.extract <- function(dataf, timecols, valcols) {
	#Example: datanew <- EdR.extract(data1, c("doy_dbl", "TTc"), c("Leaf", "Stem", "Root", "Grain"))
	
	#Start to form the result
	temp1 <- dataf[timecols]				# Extract the time columns from the input data frame
	result <- temp1							# Make a copy of the time column data frame
	curr_valcol <- as.character(valcols[1])	# Get the name of the first value column
	result$value <- dataf[,curr_valcol]		# Get the values from the column
	result$value_type <- curr_valcol		# Store the name of the value column
	
	#Add the rest of the value columns
	if(length(valcols)>1) {
		for(i in 2:length(valcols)) {
			temp2 <- temp1							# Make a copy of the time column data frame
			curr_valcol <- as.character(valcols[i])	# Get the name of the current value column
			temp2$value <- dataf[,curr_valcol]		# Get the values from the column
			temp2$value_type <- curr_valcol			# Store the name of the value column
			result <- rbind(result, temp2)			# Add this to the result
		}
	}
	
	#Return the result
	return(result)
}