Class: CSV (Ruby 2.3.2)
Description: Class : CSV - Ruby 2.3.2

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Support for the Ruby 2.3 series has ended. See here for reference.

### Home Classes Methods

### In Files

- csv.rb

### Parent

Object

### Namespace

- CLASS CSV::MalformedCSVError
- CLASS CSV::Row
- CLASS CSV::Table

### Methods

- ::filter
- ::foreach
- ::generate
- ::generate_line
- ::instance
- ::new
- ::open
- ::parse
- ::parse_line
- ::read
- ::readlines
- ::table
- #<<
- #add_row
- #convert
- #converters
- #each
- #force_quotes?
- #gets
- #header_convert
- #header_converters
- #header_row?
- #headers
- #inspect
- #puts
- #read
- #readline
- #readlines
- #return_headers?
- #rewind
- #shift
- #skip_blanks?
- #unconverted_fields?
- #write_headers?

### Included Modules

- Enumerable

### Class/Module Index

Quicksearch

- CSV
- CSV::MalformedCSVError
- CSV::Row
- CSV::Table
- Object

No matching classes.

# CSV

This class provides a complete interface to CSV files and data. It offers tools to enable you to read and write to and from Strings or IO objects, as needed.

## Reading¶ ↑

### From a File¶ ↑

#### A Line at a Time¶ ↑

    CSV.foreach("path/to/file.csv") do |row|
      # use row here...
    end

#### All at Once¶ ↑

    arr_of_arrs = CSV.read("path/to/file.csv")

### From a String¶ ↑

#### A Line at a Time¶ ↑

    CSV.parse("CSV,data,String") do |row|
      # use row here...
    end

#### All at Once¶ ↑

    arr_of_arrs = CSV.parse("CSV,data,String")

## Writing¶ ↑

### To a File¶ ↑

    CSV.open("path/to/file.csv", "wb") do |csv|
      csv << ["row", "of", "CSV", "data"]
      csv << ["another", "row"]
      # ...
    end

### To a String¶ ↑

    csv_string = CSV.generate do |csv|
      csv << ["row", "of", "CSV", "data"]
      csv << ["another", "row"]
      # ...
    end

## Convert a Single Line¶ ↑

    csv_string = ["CSV", "data"].to_csv   # to CSV
    csv_array  = "CSV,String".parse_csv   # from CSV

## Shortcut Interface¶ ↑

    CSV             { |csv_out| csv_out << %w{my data here} }  # to $stdout
    CSV(csv = "")   { |csv_str| csv_str << %w{my data here} }  # to a String
    CSV($stderr)    { |csv_err| csv_err << %w{my data here} }  # to $stderr
    CSV($stdin)     { |csv_in|  csv_in.each { |row| p row } }  # from $stdin

## Advanced Usage¶ ↑

### Wrap an IO Object¶ ↑

    csv = CSV.new(io, options)
    # ... read (with gets() or each()) from and write (with <<) to csv here ...

## CSV and Character Encodings (M17n or Multilingualization)¶ ↑

This new CSV parser is m17n savvy. The parser works in the Encoding of the IO or String object being read from or written to. Your data is never transcoded (unless you ask Ruby to transcode it for you) and will literally be parsed in the Encoding it is in. Thus CSV will return Arrays or Rows of Strings in the Encoding of your data. This is accomplished by transcoding the parser itself into your Encoding.

Some transcoding must take place, of course, to accomplish this multiencoding support. For example, `:col_sep`, `:row_sep`, and `:quote_char` must be transcoded to match your data. Hopefully this makes the entire process feel transparent, since CSV's defaults should just magically work for your data. However, you can set these values manually in the target Encoding to avoid the translation.

It's also important to note that while all of CSV's core parser is now Encoding agnostic, some features are not. For example, the built-in converters will try to transcode data to UTF-8 before making conversions. Again, you can provide custom converters that are aware of your Encodings to avoid this translation. It's just too hard for me to support native conversions in all of Ruby's Encodings.

Anyway, the practical side of this is simple: make sure IO and String objects passed into CSV have the proper Encoding set and everything should just work. CSV methods that allow you to open IO objects (CSV::foreach(), ::open, ::read, and ::readlines) do allow you to specify the Encoding.

One minor exception comes when generating CSV into a String with an Encoding that is not ASCII compatible. There's no existing data for CSV to use to prepare itself and thus you will probably need to manually specify the desired Encoding for most of those cases. It will try to guess using the fields in a row of output though, when using ::generate_line or Array#to_csv().

I try to point out any other Encoding issues in the documentation of methods as they come up.

This has been tested to the best of my ability with all non-“dummy” Encodings Ruby ships with. However, it is brave new code and may have some bugs. Please feel free to report any issues you find with it.

### Constants

ConverterEncoding

  The encoding used by all converters.

Converters

  This Hash holds the built-in converters of CSV that can be accessed by name. You can select Converters with #convert or through the `options` Hash passed to ::new.

  `:integer`

    Converts any field Integer() accepts.

  `:float`

    Converts any field Float() accepts.

  `:numeric`

    A combination of `:integer` and `:float`.

  `:date`

    Converts any field Date::parse() accepts.

  `:date_time`

    Converts any field DateTime::parse() accepts.

  `:all`

    All built-in converters. A combination of `:date_time` and `:numeric`.

  All built-in converters transcode field data to UTF-8 before attempting a conversion. If your data cannot be transcoded to UTF-8 the conversion will fail and the field will remain unchanged.

  This Hash is intentionally left unfrozen and users should feel free to add values to it that can be accessed by all CSV objects.

  To add a combo field, the value should be an Array of names. Combo fields can be nested with other combo fields.

DEFAULT_OPTIONS

  The options used when no overrides are given by calling code. They are:

  `:col_sep`

    `","`

  `:row_sep`

    `:auto`

  `:quote_char`

    `'"'`

  `:field_size_limit`

    `nil`

  `:converters`

    `nil`

  `:unconverted_fields`

    `nil`

  `:headers`

    `false`

  `:return_headers`

    `false`

  `:header_converters`

    `nil`

  `:skip_blanks`

    `false`

  `:force_quotes`

    `false`

  `:skip_lines`

    `nil`

DateMatcher

  A Regexp used to find and convert some common Date formats.

DateTimeMatcher

  A Regexp used to find and convert some common DateTime formats.

FieldInfo

  A FieldInfo Struct contains details about a field's position in the data source it was read from. CSV will pass this Struct to some blocks that make decisions based on field structure. See CSV.convert_fields() for an example.

  `index`

    The zero-based index of the field in its row.

  `line`

    The line of the data source this row is from.

  `header`

    The header for the column, when available.

HeaderConverters

  This Hash holds the built-in header converters of CSV that can be accessed by name. You can select HeaderConverters with #header_convert or through the `options` Hash passed to ::new.

  `:downcase`

    Calls downcase() on the header String.

  `:symbol`

    The header String is downcased, spaces are replaced with underscores, non-word characters are dropped, and finally to_sym() is called.

  All built-in header converters transcode header data to UTF-8 before attempting a conversion. If your data cannot be transcoded to UTF-8 the conversion will fail and the header will remain unchanged.

  This Hash is intentionally left unfrozen and users should feel free to add values to it that can be accessed by all CSV objects.

  To add a combo field, the value should be an Array of names. Combo fields can be nested with other combo fields.

VERSION

  The version of the installed library.

### Attributes

col_sep[R]

The encoded `:col_sep` used in parsing and writing. See ::new for details.

encoding[R]

The Encoding CSV is parsing or writing in. This will be the Encoding you receive parsed data in and/or the Encoding data will be written in.

field_size_limit[R]

The limit for field size, if any. See ::new for details.

lineno[R]

The line number of the last row read from this file. Fields with nested line-end characters will not affect this count.

quote_char[R]

The encoded `:quote_char` used in parsing and writing. See ::new for details.

row_sep[R]

The encoded `:row_sep` used in parsing and writing. See ::new for details.

skip_lines[R]

The regex marking a line as a comment. See ::new for details

### Public Class Methods

filter( options = Hash.new ) { |row| ... } click to toggle source
filter( input, options = Hash.new ) { |row| ... }
filter( input, output, options = Hash.new ) { |row| ... }

This method is a convenience for building Unix-like filters for CSV data. Each row is yielded to the provided block which can alter it as needed. After the block returns, the row is appended to `output` altered or not.

The `input` and `output` arguments can be anything ::new accepts (generally String or IO objects). If not given, they default to `ARGF` and `$stdout`.

The `options` parameter is also filtered down to ::new after some clever key parsing. Any key beginning with `:in_` or `:input_` will have that leading identifier stripped and will only be used in the `options` Hash for the `input` object. Keys starting with `:out_` or `:output_` affect only `output`. All other keys are assigned to both objects.

The `:output_row_sep` `option` defaults to `$INPUT_RECORD_SEPARATOR` (`$/`).

                   # File csv.rb, line 1085
    def self.filter(*args)
      # parse options for input, output, or both
      in_options, out_options = Hash.new, {row_sep: $INPUT_RECORD_SEPARATOR}
      if args.last.is_a? Hash
        args.pop.each do |key, value|
          case key.to_s
          when /\Ain(?:put)?_(.+)\Z/
            in_options[$1.to_sym] = value
          when /\Aout(?:put)?_(.+)\Z/
            out_options[$1.to_sym] = value
          else
            in_options[key]  = value
            out_options[key] = value
          end
        end
      end
      # build input and output wrappers
      input  = new(args.shift || ARGF,    in_options)
      output = new(args.shift || $stdout, out_options)

      # read, yield, write
      input.each do |row|
        yield row
        output << row
      end
    end

foreach(path, options = Hash.new, &block) click to toggle source

This method is intended as the primary interface for reading CSV files. You pass a `path` and any `options` you wish to set for the read. Each row of file will be passed to the provided `block` in turn.

The `options` parameter can be anything ::new understands. This method also understands an additional `:encoding` parameter that you can use to specify the Encoding of the data in the file to be read. You must provide this unless your data is in Encoding::default_external(). CSV will use this to determine how to parse the data. You may provide a second Encoding to have the data transcoded as it is read. For example, `encoding: "UTF-32BE:UTF-8"` would read UTF-32BE data from the file but transcode it to UTF-8 before CSV parses it.

                   # File csv.rb, line 1126
    def self.foreach(path, options = Hash.new, &block)
      return to_enum(__method__, path, options) unless block
      open(path, options) do |csv|
        csv.each(&block)
      end
    end

generate( str, options = Hash.new ) { |csv| ... } click to toggle source
generate( options = Hash.new ) { |csv| ... }

This method wraps a String you provide, or an empty default String, in a CSV object which is passed to the provided block. You can use the block to append CSV rows to the String and when the block exits, the final String will be returned.

Note that a passed String is modified by this method. Call dup() before passing if you need a new String.

The `options` parameter can be anything ::new understands. This method understands an additional `:encoding` parameter when not passed a String to set the base Encoding for the output. CSV needs this hint if you plan to output non-ASCII compatible data.

                   # File csv.rb, line 1151
    def self.generate(*args)
      # add a default empty String, if none was given
      if args.first.is_a? String
        io = StringIO.new(args.shift)
        io.seek(0, IO::SEEK_END)
        args.unshift(io)
      else
        encoding = args[-1][:encoding] if args.last.is_a?(Hash)
        str      = String.new
        str.force_encoding(encoding) if encoding
        args.unshift(str)
      end
      csv = new(*args)  # wrap
      yield csv         # yield for appending
      csv.string        # return final String
    end

generate_line(row, options = Hash.new) click to toggle source

This method is a shortcut for converting a single row (Array) into a CSV String.

The `options` parameter can be anything ::new understands. This method understands an additional `:encoding` parameter to set the base Encoding for the output. This method will try to guess your Encoding from the first non-`nil` field in `row`, if possible, but you may need to use this parameter as a backup plan.

The `:row_sep` `option` defaults to `$INPUT_RECORD_SEPARATOR` (`$/`) when calling this method.

                   # File csv.rb, line 1181
    def self.generate_line(row, options = Hash.new)
      options  = {row_sep: $INPUT_RECORD_SEPARATOR}.merge(options)
      encoding = options.delete(:encoding)
      str      = String.new
      if encoding
        str.force_encoding(encoding)
      elsif field = row.find { |f| not f.nil? }
        str.force_encoding(String(field).encoding)
      end
      (new(str, options) << row).string
    end

instance(data = $stdout, options = Hash.new) click to toggle source

This method will return a CSV instance, just like ::new, but the instance will be cached and returned for all future calls to this method for the same `data` object (tested by Object#object_id()) with the same `options`.

If a block is given, the instance is passed to the block and the return value becomes the return value of the block.

                   # File csv.rb, line 1045
    def self.instance(data = $stdout, options = Hash.new)
      # create a _signature_ for this method call, data object and options
      sig = [data.object_id] +
            options.values_at(*DEFAULT_OPTIONS.keys.sort_by { |sym| sym.to_s })

      # fetch or create the instance for this signature
      @@instances ||= Hash.new
      instance    =   (@@instances[sig] ||= new(data, options))

      if block_given?
        yield instance  # run block, if given, returning result
      else
        instance        # or return the instance
      end
    end

new(data, options = Hash.new) click to toggle source

This constructor will wrap either a String or IO object passed in `data` for reading and/or writing. In addition to the CSV instance methods, several IO methods are delegated. (See ::open for a complete list.) If you pass a String for `data`, you can later retrieve it (after writing to it, for example) with CSV.string().

Note that a wrapped String will be positioned at the beginning (for reading). If you want it at the end (for writing), use ::generate. If you want any other positioning, pass a preset StringIO object instead.

You may set any reading and/or writing preferences in the `options` Hash. Available options are:

`:col_sep`

  The String placed between each field. This String will be transcoded into the data's Encoding before parsing.

`:row_sep`

  The String appended to the end of each row. This can be set to the special `:auto` setting, which requests that CSV automatically discover this from the data. Auto-discovery reads ahead in the data looking for the next `"\r\n"`, `"\n"`, or `"\r"` sequence. A sequence will be selected even if it occurs in a quoted field, assuming that you would have the same line endings there. If none of those sequences is found, `data` is `ARGF`, `STDIN`, `STDOUT`, or `STDERR`, or the stream is only available for output, the default `$INPUT_RECORD_SEPARATOR` (`$/`) is used. Obviously, discovery takes a little time. Set manually if speed is important. Also note that IO objects should be opened in binary mode on Windows if this feature will be used as the line-ending translation can cause problems with resetting the document position to where it was before the read ahead. This String will be transcoded into the data's Encoding before parsing.

`:quote_char`

  The character used to quote fields. This has to be a single character String. This is useful for application that incorrectly use `'` as the quote character instead of the correct `"`. CSV will always consider a double sequence of this character to be an escaped quote. This String will be transcoded into the data's Encoding before parsing.

`:field_size_limit`

  This is a maximum size CSV will read ahead looking for the closing quote for a field. (In truth, it reads to the first line ending beyond this size.) If a quote cannot be found within the limit CSV will raise a MalformedCSVError, assuming the data is faulty. You can use this limit to prevent what are effectively DoS attacks on the parser. However, this limit can cause a legitimate parse to fail and thus is set to `nil`, or off, by default.

`:converters`

  An Array of names from the Converters Hash and/or lambdas that handle custom conversion. A single converter doesn't have to be in an Array. All built-in converters try to transcode fields to UTF-8 before converting. The conversion will fail if the data cannot be transcoded, leaving the field unchanged.

`:unconverted_fields`

  If set to `true`, an unconverted_fields() method will be added to all returned rows (Array or CSV::Row) that will return the fields as they were before conversion. Note that `:headers` supplied by Array or String were not fields of the document and thus will have an empty Array attached.

`:headers`

  If set to `:first_row` or `true`, the initial row of the CSV file will be treated as a row of headers. If set to an Array, the contents will be used as the headers. If set to a String, the String is run through a call of ::parse_line with the same `:col_sep`, `:row_sep`, and `:quote_char` as this instance to produce an Array of headers. This setting causes #shift to return rows as CSV::Row objects instead of Arrays and #read to return CSV::Table objects instead of an Array of Arrays.

`:return_headers`

  When `false`, header rows are silently swallowed. If set to `true`, header rows are returned in a CSV::Row object with identical headers and fields (save that the fields do not go through the converters).

`:write_headers`

  When `true` and `:headers` is set, a header row will be added to the output.

`:header_converters`

  Identical in functionality to `:converters` save that the conversions are only made to header rows. All built-in converters try to transcode headers to UTF-8 before converting. The conversion will fail if the data cannot be transcoded, leaving the header unchanged.

`:skip_blanks`

  When set to a `true` value, CSV will skip over any empty rows. Note that this setting will not skip rows that contain column separators, even if the rows contain no actual data. If you want to skip rows that contain separators but no content, consider using `:skip_lines`, or inspecting fields.compact.empty? on each row.

`:force_quotes`

  When set to a `true` value, CSV will quote all CSV fields it creates.

`:skip_lines`

  When set to an object responding to `match`, every line matching it is considered a comment and ignored during parsing. When set to a String, it is first converted to a Regexp. When set to `nil` no line is considered a comment. If the passed object does not respond to `match`, `ArgumentError` is thrown.

See CSV::DEFAULT_OPTIONS for the default settings.

Options cannot be overridden in the instance methods for performance reasons, so be sure to set what you want here.

                   # File csv.rb, line 1506
    def initialize(data, options = Hash.new)
      if data.nil?
        raise ArgumentError.new("Cannot parse nil as CSV")
      end

      # build the options for this read/write
      options = DEFAULT_OPTIONS.merge(options)

      # create the IO object we will read from
      @io       = data.is_a?(String) ? StringIO.new(data) : data
      # honor the IO encoding if we can, otherwise default to ASCII-8BIT
      @encoding = raw_encoding(nil) ||
                  ( if encoding = options.delete(:internal_encoding)
                      case encoding
                      when Encoding; encoding
                      else Encoding.find(encoding)
                      end
                    end ) ||
                  ( case encoding = options.delete(:encoding)
                    when Encoding; encoding
                    when /\A[^:]+/; Encoding.find($&)
                    end ) ||
                  Encoding.default_internal || Encoding.default_external
      #
      # prepare for building safe regular expressions in the target encoding,
      # if we can transcode the needed characters
      #
      @re_esc   =   "\\".encode(@encoding).freeze rescue ""
      @re_chars =   /#{%"[-\\]\\[\\.^$?*+{}()|# \r\n\t\f\v]".encode(@encoding)}/

      init_separators(options)
      init_parsers(options)
      init_converters(options)
      init_headers(options)
      init_comments(options)

      @force_encoding = !!(encoding || options.delete(:encoding))
      options.delete(:internal_encoding)
      options.delete(:external_encoding)
      unless options.empty?
        raise ArgumentError, "Unknown options:  #{options.keys.join(', ')}."
      end

      # track our own lineno since IO gets confused about line-ends is CSV fields
      @lineno = 0
    end

open( filename, mode = "rb", options = Hash.new ) { |faster_csv| ... } click to toggle source
open( filename, options = Hash.new ) { |faster_csv| ... }
open( filename, mode = "rb", options = Hash.new )
open( filename, options = Hash.new )

This method opens an IO object, and wraps that with CSV. This is intended as the primary interface for writing a CSV file.

You must pass a `filename` and may optionally add a `mode` for Ruby's open(). You may also pass an optional Hash containing any `options` ::new understands as the final argument.

This method works like Ruby's open() call, in that it will pass a CSV object to a provided block and close it when the block terminates, or it will return the CSV object when no block is provided. (Note: This is different from the Ruby 1.8 CSV library which passed rows to the block. Use ::foreach for that behavior.)

You must provide a `mode` with an embedded Encoding designator unless your data is in Encoding::default_external(). CSV will check the Encoding of the underlying IO object (set by the `mode` you pass) to determine how to parse the data. You may provide a second Encoding to have the data transcoded as it is read just as you can with a normal call to IO::open(). For example, `"rb:UTF-32BE:UTF-8"` would read UTF-32BE data from the file but transcode it to UTF-8 before CSV parses it.

An opened CSV object will delegate to many IO methods for convenience. You may call:

- binmode()

- binmode?()

- close()

- close_read()

- close_write()

- closed?()

- eof()

- eof?()

- external_encoding()

- fcntl()

- fileno()

- flock()

- flush()

- fsync()

- internal_encoding()

- ioctl()

- isatty()

- path()

- pid()

- pos()

- pos=()

- reopen()

- seek()

- stat()

- sync()

- sync=()

- tell()

- to_i()

- to_io()

- truncate()

- tty?()

                   # File csv.rb, line 1256
    def self.open(*args)
      # find the +options+ Hash
      options = if args.last.is_a? Hash then args.pop else Hash.new end
      # wrap a File opened with the remaining +args+ with no newline
      # decorator
      file_opts = {universal_newline: false}.merge(options)
      begin
        f = File.open(*args, file_opts)
      rescue ArgumentError => e
        raise unless /needs binmode/ =~ e.message and args.size == 1
        args << "rb"
        file_opts = {encoding: Encoding.default_external}.merge(file_opts)
        retry
      end
      begin
        csv = new(f, options)
      rescue Exception
        f.close
        raise
      end

      # handle blocks like Ruby's open(), not like the CSV library
      if block_given?
        begin
          yield csv
        ensure
          csv.close
        end
      else
        csv
      end
    end

parse( str, options = Hash.new ) { |row| ... } click to toggle source
parse( str, options = Hash.new )

This method can be used to easily parse CSV out of a String. You may either provide a `block` which will be called with each row of the String in turn, or just use the returned Array of Arrays (when no `block` is given).

You pass your `str` to read from, and an optional `options` Hash containing anything ::new understands.

                   # File csv.rb, line 1301
    def self.parse(*args, &block)
      csv = new(*args)
      if block.nil?  # slurp contents, if no block is given
        begin
          csv.read
        ensure
          csv.close
        end
      else           # or pass each row to a provided block
        csv.each(&block)
      end
    end

parse_line(line, options = Hash.new) click to toggle source

This method is a shortcut for converting a single line of a CSV String into an Array. Note that if `line` contains multiple rows, anything beyond the first row is ignored.

The `options` parameter can be anything ::new understands.

                   # File csv.rb, line 1321
    def self.parse_line(line, options = Hash.new)
      new(line, options).shift
    end

read(path, *options) click to toggle source

Use to slurp a CSV file into an Array of Arrays. Pass the `path` to the file and any `options` ::new understands. This method also understands an additional `:encoding` parameter that you can use to specify the Encoding of the data in the file to be read. You must provide this unless your data is in Encoding::default_external(). CSV will use this to determine how to parse the data. You may provide a second Encoding to have the data transcoded as it is read. For example, `encoding: "UTF-32BE:UTF-8"` would read UTF-32BE data from the file but transcode it to UTF-8 before CSV parses it.

                   # File csv.rb, line 1336
    def self.read(path, *options)
      open(path, *options) { |csv| csv.read }
    end

readlines(*args) click to toggle source

Alias for ::read.

                   # File csv.rb, line 1341
    def self.readlines(*args)
      read(*args)
    end

table(path, options = Hash.new) click to toggle source

A shortcut for:

    CSV.read( path, { headers:           true,
                      converters:        :numeric,
                      header_converters: :symbol }.merge(options) )

                   # File csv.rb, line 1352
    def self.table(path, options = Hash.new)
      read( path, { headers:           true,
                    converters:        :numeric,
                    header_converters: :symbol }.merge(options) )
    end

### Public Instance Methods

<<(row) click to toggle source

The primary write method for wrapped Strings and IOs, `row` (an Array or CSV::Row) is converted to CSV and appended to the data source. When a CSV::Row is passed, only the row's fields() are appended to the output.

The data source must be open for writing.

                   # File csv.rb, line 1663
    def <<(row)
      # make sure headers have been assigned
      if header_row? and [Array, String].include? @use_headers.class
        parse_headers  # won't read data for Array or String
        self << @headers if @write_headers
      end

      # handle CSV::Row objects and Hashes
      row = case row
            when self.class::Row then row.fields
            when Hash            then @headers.map { |header| row[header] }
            else                      row
            end

      @headers =  row if header_row?
      @lineno  += 1

      output = row.map(&@quote).join(@col_sep) + @row_sep  # quote and separate
      if @io.is_a?(StringIO)             and
         output.encoding != (encoding = raw_encoding)
        if @force_encoding
          output = output.encode(encoding)
        elsif (compatible_encoding = Encoding.compatible?(@io.string, output))
          @io.set_encoding(compatible_encoding)
          @io.seek(0, IO::SEEK_END)
        end
      end
      @io << output

      self  # for chaining
    end

Also aliased as: add_row, puts
add_row(row) click to toggle source
Alias for: <<
convert( name ) click to toggle source
convert { |field| ... }
convert { |field, field_info| ... }

You can use this method to install a CSV::Converters built-in, or provide a block that handles a custom conversion.

If you provide a block that takes one argument, it will be passed the field and is expected to return the converted value or the field itself. If your block takes two arguments, it will also be passed a CSV::FieldInfo Struct, containing details about the field. Again, the block should return a converted field or the field itself.

                   # File csv.rb, line 1712
    def convert(name = nil, &converter)
      add_converter(:converters, self.class::Converters, name, &converter)
    end

converters() click to toggle source

Returns the current list of converters in effect. See ::new for details. Built-in converters will be returned by name, while others will be returned as is.

                   # File csv.rb, line 1579
    def converters
      @converters.map do |converter|
        name = Converters.rassoc(converter)
        name ? name.first : converter
      end
    end

each() click to toggle source

Yields each row of the data source in turn.

Support for Enumerable.

The data source must be open for reading.

                   # File csv.rb, line 1743
    def each
      if block_given?
        while row = shift
          yield row
        end
      else
        to_enum
      end
    end

force_quotes?() click to toggle source

Returns `true` if all output fields are quoted. See ::new for details.

                   # File csv.rb, line 1622
    def force_quotes?()       @force_quotes       end

gets() click to toggle source
Alias for: shift
header_convert( name ) click to toggle source
header_convert { |field| ... }
header_convert { |field, field_info| ... }

Identical to #convert, but for header rows.

Note that this method must be called before header rows are read to have any effect.

                   # File csv.rb, line 1727
    def header_convert(name = nil, &converter)
      add_converter( :header_converters,
                     self.class::HeaderConverters,
                     name,
                     &converter )
    end

header_converters() click to toggle source

Returns the current list of converters in effect for headers. See ::new for details. Built-in converters will be returned by name, while others will be returned as is.

                   # File csv.rb, line 1610
    def header_converters
      @header_converters.map do |converter|
        name = HeaderConverters.rassoc(converter)
        name ? name.first : converter
      end
    end

header_row?() click to toggle source

Returns `true` if the next row read will be a header row.

                   # File csv.rb, line 1769
    def header_row?
      @use_headers and @headers.nil?
    end

headers() click to toggle source

Returns `nil` if headers will not be used, `true` if they will but have not yet been read, or the actual headers after they have been read. See ::new for details.

                   # File csv.rb, line 1595
    def headers
      @headers || true if @use_headers
    end

inspect() click to toggle source

Returns a simplified description of the key CSV attributes in an ASCII compatible String.

                   # File csv.rb, line 1930
    def inspect
      str = ["<#", self.class.to_s, " io_type:"]
      # show type of wrapped IO
      if    @io == $stdout then str << "$stdout"
      elsif @io == $stdin  then str << "$stdin"
      elsif @io == $stderr then str << "$stderr"
      else                      str << @io.class.to_s
      end
      # show IO.path(), if available
      if @io.respond_to?(:path) and (p = @io.path)
        str << " io_path:" << p.inspect
      end
      # show encoding
      str << " encoding:" << @encoding.name
      # show other attributes
      %w[ lineno     col_sep     row_sep
          quote_char skip_blanks ].each do |attr_name|
        if a = instance_variable_get("@#{attr_name}")
          str << " " << attr_name << ":" << a.inspect
        end
      end
      if @use_headers
        str << " headers:" << headers.inspect
      end
      str << ">"
      begin
        str.join('')
      rescue  # any encoding error
        str.map do |s|
          e = Encoding::Converter.asciicompat_encoding(s.encoding)
          e ? s.encode(e) : s.force_encoding("ASCII-8BIT")
        end.join('')
      end
    end

puts(row) click to toggle source
Alias for: <<
read() click to toggle source

Slurps the remaining rows and returns an Array of Arrays.

The data source must be open for reading.

                   # File csv.rb, line 1758
    def read
      rows = to_a
      if @use_headers
        Table.new(rows)
      else
        rows
      end
    end

Also aliased as: readlines
readline() click to toggle source
Alias for: shift
readlines() click to toggle source
Alias for: read
return_headers?() click to toggle source

Returns `true` if headers will be returned as a row of results. See ::new for details.

                   # File csv.rb, line 1602
    def return_headers?()     @return_headers     end

rewind() click to toggle source

Rewinds the underlying IO object and resets CSV's lineno() counter.

                   # File csv.rb, line 1647
    def rewind
      @headers = nil
      @lineno  = 0

      @io.rewind
    end

shift() click to toggle source

The primary read method for wrapped Strings and IOs, a single row is pulled from the data source, parsed and returned as an Array of fields (if header rows are not used) or a CSV::Row (when header rows are used).

The data source must be open for reading.

                   # File csv.rb, line 1780
    def shift
      #########################################################################
      ### This method is purposefully kept a bit long as simple conditional ###
      ### checks are faster than numerous (expensive) method calls.         ###
      #########################################################################

      # handle headers not based on document content
      if header_row? and @return_headers and
         [Array, String].include? @use_headers.class
        if @unconverted_fields
          return add_unconverted_fields(parse_headers, Array.new)
        else
          return parse_headers
        end
      end

      #
      # it can take multiple calls to <tt>@io.gets()</tt> to get a full line,
      # because of \r and/or \n characters embedded in quoted fields
      #
      in_extended_col = false
      csv             = Array.new

      loop do
        # add another read to the line
        unless parse = @io.gets(@row_sep)
          return nil
        end

        parse.sub!(@parsers[:line_end], "")

        if csv.empty?
          #
          # I believe a blank line should be an <tt>Array.new</tt>, not Ruby 1.8
          # CSV's <tt>[nil]</tt>
          #
          if parse.empty?
            @lineno += 1
            if @skip_blanks
              next
            elsif @unconverted_fields
              return add_unconverted_fields(Array.new, Array.new)
            elsif @use_headers
              return self.class::Row.new(Array.new, Array.new)
            else
              return Array.new
            end
          end
        end

        next if @skip_lines and @skip_lines.match parse

        parts =  parse.split(@col_sep, -1)
        if parts.empty?
          if in_extended_col
            csv[-1] << @col_sep   # will be replaced with a @row_sep after the parts.each loop
          else
            csv << nil
          end
        end

        # This loop is the hot path of csv parsing. Some things may be non-dry
        # for a reason. Make sure to benchmark when refactoring.
        parts.each do |part|
          if in_extended_col
            # If we are continuing a previous column
            if part[-1] == @quote_char && part.count(@quote_char) % 2 != 0
              # extended column ends
              csv.last << part[0..-2]
              if csv.last =~ @parsers[:stray_quote]
                raise MalformedCSVError,
                      "Missing or stray quote in line #{lineno + 1}"
              end
              csv.last.gsub!(@quote_char * 2, @quote_char)
              in_extended_col = false
            else
              csv.last << part
              csv.last << @col_sep
            end
          elsif part[0] == @quote_char
            # If we are starting a new quoted column
            if part[-1] != @quote_char || part.count(@quote_char) % 2 != 0
              # start an extended column
              csv             << part[1..-1]
              csv.last        << @col_sep
              in_extended_col =  true
            else
              # regular quoted column
              csv << part[1..-2]
              if csv.last =~ @parsers[:stray_quote]
                raise MalformedCSVError,
                      "Missing or stray quote in line #{lineno + 1}"
              end
              csv.last.gsub!(@quote_char * 2, @quote_char)
            end
          elsif part =~ @parsers[:quote_or_nl]
            # Unquoted field with bad characters.
            if part =~ @parsers[:nl_or_lf]
              raise MalformedCSVError, "Unquoted fields do not allow " +
                                       "\\r or \\n (line #{lineno + 1})."
            else
              raise MalformedCSVError, "Illegal quoting in line #{lineno + 1}."
            end
          else
            # Regular ole unquoted field.
            csv << (part.empty? ? nil : part)
          end
        end

        # Replace tacked on @col_sep with @row_sep if we are still in an extended
        # column.
        csv[-1][-1] = @row_sep if in_extended_col

        if in_extended_col
          # if we're at eof?(), a quoted field wasn't closed...
          if @io.eof?
            raise MalformedCSVError,
                  "Unclosed quoted field on line #{lineno + 1}."
          elsif @field_size_limit and csv.last.size >= @field_size_limit
            raise MalformedCSVError, "Field size exceeded on line #{lineno + 1}."
          end
          # otherwise, we need to loop and pull some more data to complete the row
        else
          @lineno += 1

          # save fields unconverted fields, if needed...
          unconverted = csv.dup if @unconverted_fields

          # convert fields, if needed...
          csv = convert_fields(csv) unless @use_headers or @converters.empty?
          # parse out header rows and handle CSV::Row conversions...
          csv = parse_headers(csv)  if     @use_headers

          # inject unconverted fields and accessor, if requested...
          if @unconverted_fields and not csv.respond_to? :unconverted_fields
            add_unconverted_fields(csv, unconverted)
          end

          # return the results
          break csv
        end
      end
    end

Also aliased as: gets, readline
skip_blanks?() click to toggle source

Returns `true` blank lines are skipped by the parser. See ::new for details.

                   # File csv.rb, line 1620
    def skip_blanks?()        @skip_blanks        end

unconverted_fields?() click to toggle source

Returns `true` if unconverted_fields() to parsed results. See ::new for details.

                   # File csv.rb, line 1589
    def unconverted_fields?() @unconverted_fields end

write_headers?() click to toggle source

Returns `true` if headers are written in output. See ::new for details.

                   # File csv.rb, line 1604
    def write_headers?()      @write_headers      end