Class FasterCSV
In: lib/faster_csv.rb
Parent: Object

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

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

All at Once

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

From a String

A Line at a Time

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

All at Once

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

Writing

To a File

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

To a String

  csv_string = FasterCSV.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

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

Advanced Usage

Wrap an IO Object

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

Methods

Included Modules

Enumerable

Classes and Modules

Class FasterCSV::MalformedCSVError
Class FasterCSV::Row
Class FasterCSV::Table

Constants

VERSION = "1.5.5".freeze   The version of the installed library.
FieldInfo = Struct.new(:index, :line, :header)   A FieldInfo Struct contains details about a field‘s position in the data source it was read from. FasterCSV will pass this Struct to some blocks that make decisions based on field structure. See FasterCSV.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.
DateMatcher = / \A(?: (\w+,?\s+)?\w+\s+\d{1,2},?\s+\d{2,4} | \d{4}-\d{2}-\d{2} )\z /x   A Regexp used to find and convert some common Date formats.
DateTimeMatcher = / \A(?: (\w+,?\s+)?\w+\s+\d{1,2}\s+\d{1,2}:\d{1,2}:\d{1,2},?\s+\d{2,4} | \d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2} )\z /x   A Regexp used to find and convert some common DateTime formats.
Converters = { :integer => lambda { |f| Integer(f) rescue f }, :float => lambda { |f| Float(f) rescue f }, :numeric => [:integer, :float], :date => lambda { |f| f =~ DateMatcher ? (Date.parse(f) rescue f) : f   This Hash holds the built-in converters of FasterCSV that can be accessed by name. You can select Converters with FasterCSV.convert() or through the options Hash passed to FasterCSV::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.

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

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

HeaderConverters = { :downcase => lambda { |h| h.downcase }, :symbol => lambda { |h| h.downcase.tr(" ", "_").delete("^a-z0-9_").to_sym   This Hash holds the built-in header converters of FasterCSV that can be accessed by name. You can select HeaderConverters with FasterCSV.header_convert() or through the options Hash passed to FasterCSV::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.

This Hash is intetionally left unfrozen and users should feel free to add values to it that can be accessed by all FasterCSV 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 = { :col_sep => ",", :row_sep => :auto, :quote_char => '"', :converters => nil, :unconverted_fields => nil, :headers => false, :return_headers => false, :header_converters => nil, :skip_blanks => false, :force_quotes => false }.freeze   The options used when no overrides are given by calling code. They are:
:col_sep:","
:row_sep::auto
:quote_char:’"’
:converters:nil
:unconverted_fields:nil
:headers:false
:return_headers:false
:header_converters:nil
:skip_blanks:false
:force_quotes:false

Attributes

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

Public Class methods

This method will build a drop-in replacement for many of the standard CSV methods. It allows you to write code like:

  begin
    require "faster_csv"
    FasterCSV.build_csv_interface
  rescue LoadError
    require "csv"
  end
  # ... use CSV here ...

This is not a complete interface with completely identical behavior. However, it is intended to be close enough that you won‘t notice the difference in most cases. CSV methods supported are:

Be warned that this interface is slower than vanilla FasterCSV due to the extra layer of method calls. Depending on usage, this can slow it down to near CSV speeds.

[Source]

# File lib/faster_csv.rb, line 874
    def self.build_csv_interface
      Object.const_set(:CSV, Class.new).class_eval do
        def self.foreach(path, rs = :auto, &block)  # :nodoc:
          FasterCSV.foreach(path, :row_sep => rs, &block)
        end

        def self.generate_line(row, fs = ",", rs = "")  # :nodoc:
          FasterCSV.generate_line(row, :col_sep => fs, :row_sep => rs)
        end

        def self.open(path, mode, fs = ",", rs = :auto, &block)  # :nodoc:
          if block and mode.include? "r"
            FasterCSV.open(path, mode, :col_sep => fs, :row_sep => rs) do |csv|
              csv.each(&block)
            end
          else
            FasterCSV.open(path, mode, :col_sep => fs, :row_sep => rs, &block)
          end
        end

        def self.parse(str_or_readable, fs = ",", rs = :auto, &block)  # :nodoc:
          FasterCSV.parse(str_or_readable, :col_sep => fs, :row_sep => rs, &block)
        end

        def self.parse_line(src, fs = ",", rs = :auto)  # :nodoc:
          FasterCSV.parse_line(src, :col_sep => fs, :row_sep => rs)
        end

        def self.readlines(path, rs = :auto)  # :nodoc:
          FasterCSV.readlines(path, :row_sep => rs)
        end
      end
    end

[Source]

# File lib/faster_csv.rb, line 12
    def self.const_missing(*_)
      raise NotImplementedError, "Please switch to Ruby 1.9's standard CSV "  +
                                 "library.  It's FasterCSV plus support for " +
                                 "Ruby 1.9's m17n encoding engine."
    end

This method allows you to serialize an Array of Ruby objects to a String or File of CSV data. This is not as powerful as Marshal or YAML, but perhaps useful for spreadsheet and database interaction.

Out of the box, this method is intended to work with simple data objects or Structs. It will serialize a list of instance variables and/or Struct.members().

If you need need more complicated serialization, you can control the process by adding methods to the class to be serialized.

A class method csv_meta() is responsible for returning the first row of the document (as an Array). This row is considered to be a Hash of the form key_1,value_1,key_2,value_2,… FasterCSV::load() expects to find a class key with a value of the stringified class name and FasterCSV::dump() will create this, if you do not define this method. This method is only called on the first object of the Array.

The next method you can provide is an instance method called csv_headers(). This method is expected to return the second line of the document (again as an Array), which is to be used to give each column a header. By default, FasterCSV::load() will set an instance variable if the field header starts with an @ character or call send() passing the header as the method name and the field value as an argument. This method is only called on the first object of the Array.

Finally, you can provide an instance method called csv_dump(), which will be passed the headers. This should return an Array of fields that can be serialized for this object. This method is called once for every object in the Array.

The io parameter can be used to serialize to a File, and options can be anything FasterCSV::new() accepts.

[Source]

# File lib/faster_csv.rb, line 943
    def self.dump(ary_of_objs, io = "", options = Hash.new)
      obj_template = ary_of_objs.first

      csv = FasterCSV.new(io, options)

      # write meta information
      begin
        csv << obj_template.class.csv_meta
      rescue NoMethodError
        csv << [:class, obj_template.class]
      end

      # write headers
      begin
        headers = obj_template.csv_headers
      rescue NoMethodError
        headers = obj_template.instance_variables.sort
        if obj_template.class.ancestors.find { |cls| cls.to_s =~ /\AStruct\b/ }
          headers += obj_template.members.map { |mem| "#{mem}=" }.sort
        end
      end
      csv << headers

      # serialize each object
      ary_of_objs.each do |obj|
        begin
          csv << obj.csv_dump(headers)
        rescue NoMethodError
          csv << headers.map do |var|
            if var[0] == ?@
              obj.instance_variable_get(var)
            else
              obj[var[0..-2]]
            end
          end
        end
      end

      if io.is_a? String
        csv.string
      else
        csv.close
      end
    end

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 FasterCSV::new() accepts (generally String or IO objects). If not given, they default to ARGF and $stdout.

The options parameter is also filtered down to FasterCSV::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 $INPUT_RECORD_SEPARATOR ($/).

[Source]

# File lib/faster_csv.rb, line 1012
    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   = FasterCSV.new(args.shift || ARGF,    in_options)
      output  = FasterCSV.new(args.shift || $stdout, out_options)

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

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 FasterCSV::new() understands.

[Source]

# File lib/faster_csv.rb, line 1046
    def self.foreach(path, options = Hash.new, &block)
      open(path, "rb", options) do |csv|
        csv.each(&block)
      end
    end

This method wraps a String you provide, or an empty default String, in a FasterCSV 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 modfied by this method. Call dup() before passing if you need a new String.

The options parameter can be anthing FasterCSV::new() understands.

[Source]

# File lib/faster_csv.rb, line 1067
    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
        args.unshift("")
      end
      faster_csv = new(*args)  # wrap
      yield faster_csv         # yield for appending
      faster_csv.string        # return final String
    end

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

The options parameter can be anthing FasterCSV::new() understands.

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

[Source]

# File lib/faster_csv.rb, line 1090
    def self.generate_line(row, options = Hash.new)
      options = {:row_sep => $INPUT_RECORD_SEPARATOR}.merge(options)
      (new("", options) << row).string
    end

This method will return a FasterCSV instance, just like FasterCSV::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.

[Source]

# File lib/faster_csv.rb, line 1104
    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

This method is the reading counterpart to FasterCSV::dump(). See that method for a detailed description of the process.

You can customize loading by adding a class method called csv_load() which will be passed a Hash of meta information, an Array of headers, and an Array of fields for the object the method is expected to return.

Remember that all fields will be Strings after this load. If you need something else, use options to setup converters or provide a custom csv_load() implementation.

[Source]

# File lib/faster_csv.rb, line 1132
    def self.load(io_or_str, options = Hash.new)
      csv = FasterCSV.new(io_or_str, options)

      # load meta information
      meta = Hash[*csv.shift]
      cls  = meta["class"].split("::").inject(Object) do |c, const|
        c.const_get(const)
      end

      # load headers
      headers = csv.shift

      # unserialize each object stored in the file
      results = csv.inject(Array.new) do |all, row|
        begin
          obj = cls.csv_load(meta, headers, row)
        rescue NoMethodError
          obj = cls.allocate
          headers.zip(row) do |name, value|
            if name[0] == ?@
              obj.instance_variable_set(name, value)
            else
              obj.send(name, value)
            end
          end
        end
        all << obj
      end

      csv.close unless io_or_str.is_a? String

      results
    end

[Source]

# File lib/faster_csv.rb, line 18
    def self.method_missing(*_)
      const_missing
    end

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

Note that a wrapped String will be positioned at at the beginning (for reading). If you want it at the end (for writing), use FasterCSV::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.
:row_sep:The String appended to the end of each row. This can be set to the special :auto setting, which requests that FasterCSV 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.
: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 ". FasterCSV will always consider a double sequence this character to be an escaped quote.
:encoding:The encoding to use when parsing the file. Defaults to your $KDOCE setting. Valid values: `n’ or `N’ for none, `e’ or `E’ for EUC, `s’ or `S’ for SJIS, and `u’ or `U’ for UTF-8 (see Regexp.new()).
:field_size_limit:This is a maximum size FasterCSV 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 FasterCSV 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.
:unconverted_fields:If set to true, an unconverted_fields() method will be added to all returned rows (Array or FasterCSV::Row) that will return the fields as they were before convertion. 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 FasterCSV::parse_line() with the same :col_sep, :row_sep, and :quote_char as this instance to produce an Array of headers. This setting causes FasterCSV.shift() to return rows as FasterCSV::Row objects instead of Arrays and FasterCSV.read() to return FasterCSV::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 FasterCSV::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. Note that if the table only contains header rows, :return_headers must also be set in order for a header row to be output.
:header_converters:Identical in functionality to :converters save that the conversions are only made to header rows.
:skip_blanks:When set to a true value, FasterCSV will skip over any rows with no content.
:force_quotes:When set to a true value, FasterCSV will quote all CSV fields it creates.

See FasterCSV::DEFAULT_OPTIONS for the default settings.

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

[Source]

# File lib/faster_csv.rb, line 1425
    def initialize(data, options = Hash.new)
      # build the options for this read/write
      options = DEFAULT_OPTIONS.merge(options)

      # create the IO object we will read from
      @io = if data.is_a? String then StringIO.new(data) else data end

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

      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

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

You may pass any args Ruby‘s open() understands followed by an optional Hash containing any options FasterCSV::new() understands.

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

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

  • binmode()
  • close()
  • close_read()
  • close_write()
  • closed?()
  • eof()
  • eof?()
  • fcntl()
  • fileno()
  • flush()
  • fsync()
  • ioctl()
  • isatty()
  • pid()
  • pos()
  • reopen()
  • seek()
  • stat()
  • sync()
  • sync=()
  • tell()
  • to_i()
  • to_io()
  • tty?()

[Source]

# File lib/faster_csv.rb, line 1211
    def self.open(*args)
      # find the +options+ Hash
      options = if args.last.is_a? Hash then args.pop else Hash.new end
      # default to a binary open mode
      args << "rb" if args.size == 1
      # wrap a File opened with the remaining +args+
      csv     = new(File.open(*args), options)

      # 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

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 FasterCSV::new() understands.

[Source]

# File lib/faster_csv.rb, line 1243
    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

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

The options parameter can be anthing FasterCSV::new() understands.

[Source]

# File lib/faster_csv.rb, line 1263
    def self.parse_line(line, options = Hash.new)
      new(line, options).shift
    end

Use to slurp a CSV file into an Array of Arrays. Pass the path to the file and any options FasterCSV::new() understands.

[Source]

# File lib/faster_csv.rb, line 1271
    def self.read(path, options = Hash.new)
      open(path, "rb", options) { |csv| csv.read }
    end

Alias for FasterCSV::read().

[Source]

# File lib/faster_csv.rb, line 1276
    def self.readlines(*args)
      read(*args)
    end

A shortcut for:

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

[Source]

# File lib/faster_csv.rb, line 1287
    def self.table(path, options = Hash.new)
      read( path, { :headers           => true,
                    :converters        => :numeric,
                    :header_converters => :symbol }.merge(options) )
    end

Public Instance methods

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

The data source must be open for writing.

[Source]

# File lib/faster_csv.rb, line 1477
    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 FasterCSV::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

      @io << row.map(&@quote).join(@col_sep) + @row_sep  # quote and separate

      self  # for chaining
    end
add_row(row)

Alias for #<<

You can use this method to install a FasterCSV::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 FieldInfo Struct, containing details about the field. Again, the block should return a converted field or the field itself.

[Source]

# File lib/faster_csv.rb, line 1516
    def convert(name = nil, &converter)
      add_converter(:converters, self.class::Converters, name, &converter)
    end

Yields each row of the data source in turn.

Support for Enumerable.

The data source must be open for reading.

[Source]

# File lib/faster_csv.rb, line 1547
    def each
      while row = shift
        yield row
      end
    end
gets()

Alias for shift

Identical to FasterCSV.convert(), but for header rows.

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

[Source]

# File lib/faster_csv.rb, line 1531
    def header_convert(name = nil, &converter)
      add_converter( :header_converters,
                     self.class::HeaderConverters,
                     name,
                     &converter )
    end

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

[Source]

# File lib/faster_csv.rb, line 1569
    def header_row?
      @use_headers and @headers.nil?
    end

Returns a simplified description of the key FasterCSV attributes.

[Source]

# File lib/faster_csv.rb, line 1698
    def inspect
      str = "<##{self.class} 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 other attributes
      %w[ lineno     col_sep     row_sep
          quote_char skip_blanks encoding ].each do |attr_name|
        if a = instance_variable_get("@#{attr_name}")
          str << " #{attr_name}:#{a.inspect}"
        end
      end
      if @use_headers
        str << " headers:#{(@headers || true).inspect}"
      end
      str << ">"
    end

[Source]

# File lib/faster_csv.rb, line 22
    def method_missing(*_)
      self.class.const_missing
    end
puts(row)

Alias for #<<

Slurps the remaining rows and returns an Array of Arrays.

The data source must be open for reading.

[Source]

# File lib/faster_csv.rb, line 1558
    def read
      rows = to_a
      if @use_headers
        Table.new(rows)
      else
        rows
      end
    end
readline()

Alias for shift

readlines()

Alias for read

Rewinds the underlying IO object and resets FasterCSV‘s lineno() counter.

[Source]

# File lib/faster_csv.rb, line 1460
    def rewind
      @headers = nil
      @lineno  = 0

      @io.rewind
    end

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 FasterCSV::Row (when header rows are used).

The data source must be open for reading.

[Source]

# File lib/faster_csv.rb, line 1580
    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

      # begin with a blank line, so we can always add to it
      line = String.new

      # 
      # 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
      # 
      loop do
        # add another read to the line
        if read_line = @io.gets(@row_sep)
         line += read_line
        else
         return nil
        end
        # copy the line so we can chop it up in parsing
        parse =  line.dup
        parse.sub!(@parsers[:line_end], "")

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

        # parse the fields with a mix of String#split and regular expressions
        csv           = Array.new
        current_field = String.new
        field_quotes  = 0
        parse.split(@col_sep, -1).each do |match|
          if current_field.empty? && match.count(@quote_and_newlines).zero?
            csv           << (match.empty? ? nil : match)
          elsif (current_field.empty? ? match[0] : current_field[0]) ==
                @quote_char[0]
            current_field << match
            field_quotes += match.count(@quote_char)
            if field_quotes % 2 == 0
              in_quotes = current_field[@parsers[:quoted_field], 1]
              if !in_quotes || in_quotes[@parsers[:stray_quote]]
                raise MalformedCSVError,
                      "Missing or stray quote in line #{lineno + 1}"
              end
              current_field = in_quotes
              current_field.gsub!(@quote_char * 2, @quote_char) # unescape contents
              csv           << current_field
              current_field =  String.new
              field_quotes  =  0
            else # we found a quoted field that spans multiple lines
              current_field << @col_sep
            end
          elsif match.count("\r\n").zero?
            raise MalformedCSVError, "Illegal quoting in line #{lineno + 1}."
          else
            raise MalformedCSVError, "Unquoted fields do not allow " +
                                     "\\r or \\n (line #{lineno + 1})."
          end
        end

        # if parse is empty?(), we found all the fields on the line...
        if field_quotes % 2 == 0
          @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 FasterCSV::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
        # if we're not empty?() but 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 current_field.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
      end
    end

[Validate]