As mikeb pointed out, there are the docs - http://ruby-doc.org/stdlib-1.9.3/libdoc/csv/rdoc/CSV.html - Or you can follow along with the examples below (all are tested and working):
In this file we'll have two rows, a header row and data row, very simple CSV:
CSV.open("file.csv", "wb") do |csv|
csv << ["animal", "count", "price"]
csv << ["fox", "1", "$90.00"]
result, a file called "file.csv" with the following:
Almost the same forumla as above only instead of using "wb" mode, we'll use "a+" mode. For more information on these see this stack overflow answer: What are the Ruby File.open modes and options?
CSV.open("file.csv", "a+") do |csv|
csv << ["cow", "3","2500"]
Now when we open our file.csv we have:
Now you know how to copy and to write to a file, to read a CSV and therefore grab the data for manipulation you just do:
CSV.foreach("file.csv") do |row|
puts row #first row would be ["animal", "count", "price"] - etc.
Of course this is like one of like a hundred different ways you can pull info from a CSV using this gem. For more info I suggest visiting the docs now that you have a primer: http://ruby-doc.org/stdlib-1.9.3/libdoc/csv/rdoc/CSV.html
What if I want to open without writing to right away? Just don't use the block?