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.
FasterCSV.foreach("path/to/file.csv") do |row| # use row here... end
arr_of_arrs = FasterCSV.read("path/to/file.csv")
FasterCSV.parse("CSV,data,String") do |row| # use row here... end
arr_of_arrs = FasterCSV.parse("CSV,data,String")
FasterCSV.open("path/to/file.csv", "w") do |csv| csv << ["row", "of", "CSV", "data"] csv << ["another", "row"] # ... end
csv_string = FasterCSV.generate do |csv| csv << ["row", "of", "CSV", "data"] csv << ["another", "row"] # ... end
csv_string = ["CSV", "data"].to_csv # to CSV csv_array = "CSV,String".parse_csv # from CSV
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
csv = FCSV.new(io, options) # ... read (with gets() or each()) from and write (with <<) to csv here ...
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.
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 |
A Regexp used to find and convert some common Date formats.
A Regexp used to find and convert some common DateTime formats.
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. |
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.
The version of the installed library.
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:
foreach()
open()
parse()
readlines()
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.
# 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
# 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.
# 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 $INPUT_RECORD_SEPARATOR ($/).
# 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.
# 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.
# 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.
# 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.
# 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.
# 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
# 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 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, 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 $KCODE 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.
# File lib/faster_csv.rb, line 1423 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?()
# 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.
# 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 anything FasterCSV::new() understands.
# 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.
# 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().
# 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) )
# 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
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.
# File lib/faster_csv.rb, line 1475 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
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.
# File lib/faster_csv.rb, line 1514 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.
# File lib/faster_csv.rb, line 1545 def each while row = shift yield row end end
Identical to FasterCSV.convert(), but for header rows.
Note that this method must be called before header rows are read to have any effect.
# File lib/faster_csv.rb, line 1529 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.
# File lib/faster_csv.rb, line 1567 def header_row? @use_headers and @headers.nil? end
Returns a simplified description of the key FasterCSV attributes.
# File lib/faster_csv.rb, line 1696 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 ] 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
# File lib/faster_csv.rb, line 22 def method_missing(*_) self.class.const_missing end
Slurps the remaining rows and returns an Array of Arrays.
The data source must be open for reading.
# File lib/faster_csv.rb, line 1556 def read rows = to_a if @use_headers Table.new(rows) else rows end end
Rewinds the underlying IO object and resets FasterCSV's lineno() counter.
# File lib/faster_csv.rb, line 1458 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.
# File lib/faster_csv.rb, line 1578 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
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