How can I change the end of the range to a variable so that the csv file can have as many entries as the user wants without modifying the code. Here is my ruby code:

require 'csv'

puts "Student Assignment Average"

CSV.foreach("input.csv", col_sep: ',', row_sep: :auto, headers: true) do |row| #Establishing our local variables for this loop total_grade = 0 name = "" #Loop through rows with a range of 1..4 specifying how many columns starting at 1 and ending in 4 for grades (1 .. 4).each do |column_index| #Add a check for nil rows, if row is nil then skip this iteration if row[column_index] == nil next end #Grade equals current row index and converting it to integer grade = row[column_index].strip.to_i total_grade += grade #Name is set from row[0] the first column in the row name = row[0] end #Avg = total_grade/4.0 converting it to a float at the same time avg = total_grade/4.0 #Put name and average to output with a tab separating the columns puts "#{name}\t#{avg}" #End of loop, now it repeats for the remainder of the rows until done end