#312 CSV to Markdown Tables (Ruby)

How to convert comma-separated value data into markdown tables with ruby.

Notes

Converting CSV files to Markdown tables is a pretty common task I encounter, especially when generating documentation. The CSV data may come from a report, spreadsheet, or database extract, and I want to include it as a correctly formatted markdown table.

See python/csv2md for how to do this with python scripts, command line utilities, online tools, and editor extensions.

These notes provide some ruby alternatives.

To test options, I’m using a listing of the Sharpe novels by Bernard Cornwell: sharpe.csv.

csv2md gem

The csv2md gem provides a command line utility for converting csv formatted data to a GitHub Flavored Markdown table.

Example usage:

cd using_csv2md
gem install bundler
bundle install
csv2md ../sharpe.csv > README.md

See the raw output here and the rendered markdown output here.

Custom Ruby Script

Uses csv to read the input file and generate markdown. See the csv2md.rb script. The essence of the conversion is in these few lines:

def csv_to_markdown(file)
  table = CSV.read(file)
  markdown = ""
  markdown << "| " + table[0].join(" | ") + " |\n"
  markdown << "|" + (" --- |" * table[0].size) + "\n"
  table[1..-1].each do |row|
    markdown << "| " + row.join(" | ") + " |\n"
  end
  markdown
end