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class method

CSV.new

CSV.new(string)

CSV.new(io)

CSV.new(string, **options)

CSV.new(io, **options)

# File tmp/rubies/ruby-3.2.0/lib/csv.rb, line 1904
def initialize(data,
               col_sep: ",",
               row_sep: :auto,
               quote_char: '"',
               field_size_limit: nil,
               max_field_size: nil,
               converters: nil,
               unconverted_fields: nil,
               headers: false,
               return_headers: false,
               write_headers: nil,
               header_converters: nil,
               skip_blanks: false,
               force_quotes: false,
               skip_lines: nil,
               liberal_parsing: false,
               internal_encoding: nil,
               external_encoding: nil,
               encoding: nil,
               nil_value: nil,
               empty_value: "",
               strip: false,
               quote_empty: true,
               write_converters: nil,
               write_nil_value: nil,
               write_empty_value: "")
  raise ArgumentError.new("Cannot parse nil as CSV") if data.nil?

  if data.is_a?(String)
    if encoding
      if encoding.is_a?(String)
        data_external_encoding, data_internal_encoding = encoding.split(":", 2)
        if data_internal_encoding
          data = data.encode(data_internal_encoding, data_external_encoding)
        else
          data = data.dup.force_encoding(data_external_encoding)
        end
      else
        data = data.dup.force_encoding(encoding)
      end
    end
    @io = StringIO.new(data)
  else
    @io = data
  end
  @encoding = determine_encoding(encoding, internal_encoding)

  @base_fields_converter_options = {
    nil_value: nil_value,
    empty_value: empty_value,
  }
  @write_fields_converter_options = {
    nil_value: write_nil_value,
    empty_value: write_empty_value,
  }
  @initial_converters = converters
  @initial_header_converters = header_converters
  @initial_write_converters = write_converters

  if max_field_size.nil? and field_size_limit
    max_field_size = field_size_limit - 1
  end
  @parser_options = {
    column_separator: col_sep,
    row_separator: row_sep,
    quote_character: quote_char,
    max_field_size: max_field_size,
    unconverted_fields: unconverted_fields,
    headers: headers,
    return_headers: return_headers,
    skip_blanks: skip_blanks,
    skip_lines: skip_lines,
    liberal_parsing: liberal_parsing,
    encoding: @encoding,
    nil_value: nil_value,
    empty_value: empty_value,
    strip: strip,
  }
  @parser = nil
  @parser_enumerator = nil
  @eof_error = nil

  @writer_options = {
    encoding: @encoding,
    force_encoding: (not encoding.nil?),
    force_quotes: force_quotes,
    headers: headers,
    write_headers: write_headers,
    column_separator: col_sep,
    row_separator: row_sep,
    quote_character: quote_char,
    quote_empty: quote_empty,
  }

  @writer = nil
  writer if @writer_options[:write_headers]
end

Returns the new CSV object created using string or io and the specified options.

Argument string should be a String object; it will be put into a new StringIO object positioned at the beginning.
Argument io should be an IO object that is:
- Open for reading; on return, the IO object will be closed.
- Positioned at the beginning. To position at the end, for appending, use method CSV.generate. For any other positioning, pass a preset StringIO object instead.
Argument options: See:
- Options for Parsing
- Options for Generating
For performance reasons, the options cannot be overridden in a CSV object, so those specified here will endure.

In addition to the CSV instance methods, several IO methods are delegated. See Delegated Methods.

Create a CSV object from a String object:

Example

csv = CSV.new('foo,0')
csv # => #<CSV io_type:StringIO encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">

Create a CSV object from a File object:

Example

File.write('t.csv', 'foo,0')
csv = CSV.new(File.open('t.csv'))
csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">

Raises an exception if the argument is nil:

Example

# Raises ArgumentError (Cannot parse nil as CSV):
CSV.new(nil)

See also .instance .open .generate_lines .parse also in 3.3 · 3.1 · 3.0

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