Looking at the documentation for the CSV library of Ruby, I'm pretty sure this is possible and easy.
I simply need to delete the first three columns of a CSV file using Ruby but I haven't had any success getting it run.
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2What have you written? Why didn't it work?the Tin Man– the Tin Man2012-02-07 23:31:40 +00:00Commented Feb 7, 2012 at 23:31
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4 Answers
csv_table = CSV.read(file_path_in, :headers => true)
csv_table.delete("header_name")
csv_table.to_csv # => The new CSV in string format
Check the CSV::Table documentation: http://ruby-doc.org/stdlib-1.9.2/libdoc/csv/rdoc/CSV/Table.html
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csv_table = CSV.read("../path/to/file.csv", :headers => true)
keep = ["x", "y", "z"]
new_csv_table = csv_table.by_col!.delete_if do |column_name,column_values|
!keep.include? column_name
end
new_csv_table.to_csv
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What about:
require 'csv'
File.open("resfile.csv","w+") do |f|
CSV.foreach("file.csv") do |row|
f.puts(row[3..-1].join(","))
end
end
1 Comment
Edu
This code reads the data from "file.csv" and inserts it without the first 3 columns into "resfile.csv". The "resfile.csv" is indeed reset for every run. If you want it to have data appended just open it with "a+". The origin file "file.csv" is not changed at all.
I have built on a few of the questions (really liked what @fguillen did with CSV::Table) here but just made it a bit simpler to drop it into an existing project, target a file and make a quick change.
Have added byebug cause ... yes. Then also retained the headers from the original file (assuming they exist for anyone wanting to use this snippet).
The file is overwritten each time in case you want to test/tinker.
require 'csv'
require 'byebug'
in_file = './db/data/inbox/change__to_file_name.csv'
out_file = in_file + ".out"
target_col = "change_to_column_name"
csv_table = CSV.read(in_file, headers: true)
csv_table.delete(target_col)
CSV.open(out_file, 'w+', force_quotes: true) do |csv|
csv << csv_table.headers
csv_table.each_with_index do |row|
csv << row
end
end
