Ruby:Update value on specific row but keep the headers

昨天在stackoverflow上問了第一個問題，被鄙視了。。。說“This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form”。。。

問題如下：

I have a csv file with header. I need to update all values in a specific column but keep the header, and then save the file. How can I do it via csv library？

require 'csv'file_name = "path/to/file.csv"CSV.foreach(file_name, {:headers=>true}) do |row|  puts row[4]endarr = []#CSV.foreach(file_name, {:headers=>true}) {|row| arr << row}arr.each do |row|  row[4].replace("new program name")end#puts arr##CSV.open(file_name, "wb", {:headers=>true}) do |csv|  csv << ["your", "header", "value"]  arr.each {|row| csv << row}end##CSV.foreach(file_name, {:headers=>true}) do |row|  puts row[4]  end