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End of Life Ruby 3.1 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

CSV#<<

csv << row → self

Appends a row to self.

  • Argument row must be an Array object or a CSV::Row object.

  • The output stream must be open for writing.

Append Arrays:

Example
CSV.generate do |csv|
  csv << ['foo', 0]
  csv << ['bar', 1]
  csv << ['baz', 2]
end # => "foo,0\nbar,1\nbaz,2\n"

Append CSV::Rows:

Example
headers = []
CSV.generate do |csv|
  csv << CSV::Row.new(headers, ['foo', 0])
  csv << CSV::Row.new(headers, ['bar', 1])
  csv << CSV::Row.new(headers, ['baz', 2])
end # => "foo,0\nbar,1\nbaz,2\n"

Headers in CSV::Row objects are not appended:

Example
headers = ['Name', 'Count']
CSV.generate do |csv|
  csv << CSV::Row.new(headers, ['foo', 0])
  csv << CSV::Row.new(headers, ['bar', 1])
  csv << CSV::Row.new(headers, ['baz', 2])
end # => "foo,0\nbar,1\nbaz,2\n"

Raises an exception if row is not an Array or CSV::Row:

Example
CSV.generate do |csv|
  # Raises NoMethodError (undefined method `collect' for :foo:Symbol)
  csv << :foo
end

Raises an exception if the output stream is not opened for writing:

Example
path = 't.csv'
File.write(path, '')
File.open(path) do |file|
  CSV.open(file) do |csv|
    # Raises IOError (not opened for writing)
    csv << ['foo', 0]
  end
end
See also .table #add_row .readlines #binmode? also in 3.3 · 3.2 · 3.0
‹ prev.table next ›#add_row