I am trying to take an existing CSV file, add a fourth row to it, and then iterate through the second and third row to create the fourth rows values. Using Ruby I've created hashes where the headers are the keys and the column values are the hash values (ex: "id"=>"1", "new_fruit" => "apple")
My practice CSV file looks like this:practice csv file image
My goal is to create a fourth column: "brand_new" (which I was able to do) and then add values to it by concatenating the values from the second and third row (which I am stuck on). At the moment I just have a placement value (x) for the fourth columns values so I could see if adding the fourth column to the hash actually worked: Results with x = 1
Here is my code:
require 'csv'
def self.import
table = []
CSV.foreach(File.path("practice.csv"), headers: true) do |row|
table.each do |row|
row["brand_new"] = full_name
end
table << row.to_h
end
table
end
def full_name
x = 1
return x
end
# Add another col, row by row:
import.each do |row|
row["brand_new"] = full_name
end
puts import
Any suggestions or guidance would be much appreciated. Thank you.
Simplified your code a bit. I read the file first, then iterate about the read content.
Note: Change col_sep to comma or delete it to use the default if needed.
require "csv"
def self.import
table = CSV.read("practice.csv", headers: true , col_sep: ";")
table.each do |row|
row["brand_new"] = "#{row["old_fruit"]} #{row["new_fruit"]}"
end
puts table
end
I use the read method to read the CSV file content. It allows you to directly access the column/cell values.
Line 7 shows how to concatenate the column values as string:
"#{row["old_fruit"]} #{row["new_fruit"]}"
Refer to this old SO post and the CSV Ruby docs to learn more about working with CSV files.