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ruby/lib/csv.rb

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# encoding: US-ASCII
# frozen_string_literal: true
# = csv.rb -- CSV Reading and Writing
#
# Created by James Edward Gray II on 2005-10-31.
#
# See CSV for documentation.
#
# == Description
#
# Welcome to the new and improved CSV.
#
# This version of the CSV library began its life as FasterCSV. FasterCSV was
# intended as a replacement to Ruby's then standard CSV library. It was
# designed to address concerns users of that library had and it had three
# primary goals:
#
# 1. Be significantly faster than CSV while remaining a pure Ruby library.
# 2. Use a smaller and easier to maintain code base. (FasterCSV eventually
# grew larger, was also but considerably richer in features. The parsing
# core remains quite small.)
# 3. Improve on the CSV interface.
#
# Obviously, the last one is subjective. I did try to defer to the original
# interface whenever I didn't have a compelling reason to change it though, so
# hopefully this won't be too radically different.
#
# We must have met our goals because FasterCSV was renamed to CSV and replaced
# the original library as of Ruby 1.9. If you are migrating code from 1.8 or
# earlier, you may have to change your code to comply with the new interface.
#
# == What's the Different From the Old CSV?
#
# I'm sure I'll miss something, but I'll try to mention most of the major
# differences I am aware of, to help others quickly get up to speed:
#
# === \CSV Parsing
#
# * This parser is m17n aware. See CSV for full details.
# * This library has a stricter parser and will throw MalformedCSVErrors on
# problematic data.
# * This library has a less liberal idea of a line ending than CSV. What you
# set as the <tt>:row_sep</tt> is law. It can auto-detect your line endings
# though.
# * The old library returned empty lines as <tt>[nil]</tt>. This library calls
# them <tt>[]</tt>.
# * This library has a much faster parser.
#
# === Interface
#
# * CSV now uses Hash-style parameters to set options.
# * CSV no longer has generate_row() or parse_row().
# * The old CSV's Reader and Writer classes have been dropped.
# * CSV::open() is now more like Ruby's open().
# * CSV objects now support most standard IO methods.
# * CSV now has a new() method used to wrap objects like String and IO for
# reading and writing.
# * CSV::generate() is different from the old method.
# * CSV no longer supports partial reads. It works line-by-line.
# * CSV no longer allows the instance methods to override the separators for
# performance reasons. They must be set in the constructor.
#
# If you use this library and find yourself missing any functionality I have
# trimmed, please {let me know}[mailto:james@grayproductions.net].
#
# == Documentation
#
# See CSV for documentation.
#
# == What is CSV, really?
#
# CSV maintains a pretty strict definition of CSV taken directly from
# {the RFC}[http://www.ietf.org/rfc/rfc4180.txt]. I relax the rules in only one
# place and that is to make using this library easier. CSV will parse all valid
# CSV.
#
# What you don't want to do is to feed CSV invalid data. Because of the way the
# CSV format works, it's common for a parser to need to read until the end of
# the file to be sure a field is invalid. This consumes a lot of time and memory.
#
# Luckily, when working with invalid CSV, Ruby's built-in methods will almost
# always be superior in every way. For example, parsing non-quoted fields is as
# easy as:
#
# data.split(",")
#
# == Questions and/or Comments
#
# Feel free to email {James Edward Gray II}[mailto:james@grayproductions.net]
# with any questions.
require "forwardable"
require "date"
require "stringio"
require_relative "csv/fields_converter"
require_relative "csv/input_record_separator"
require_relative "csv/match_p"
require_relative "csv/parser"
require_relative "csv/row"
require_relative "csv/table"
require_relative "csv/writer"
using CSV::MatchP if CSV.const_defined?(:MatchP)
# == \CSV
# \CSV (comma-separated variables) data is a text representation of a table:
# - A _row_ _separator_ delimits table rows.
# A common row separator is the newline character <tt>"\n"</tt>.
# - A _column_ _separator_ delimits fields in a row.
# A common column separator is the comma character <tt>","</tt>.
#
# This \CSV \String, with row separator <tt>"\n"</tt>
# and column separator <tt>","</tt>,
# has three rows and two columns:
# "foo,0\nbar,1\nbaz,2\n"
#
# Despite the name \CSV, a \CSV representation can use different separators.
#
# For more about tables, see the Wikipedia article
# "{Table (information)}[https://en.wikipedia.org/wiki/Table_(information)]",
# especially its section
# "{Simple table}[https://en.wikipedia.org/wiki/Table_(information)#Simple_table]"
#
# == \Class \CSV
#
# Class \CSV provides methods for:
# - Parsing \CSV data from a \String object, a \File (via its file path), or an \IO object.
# - Generating \CSV data to a \String object.
#
# To make \CSV available:
# require 'csv'
#
# All examples here assume that this has been done.
#
# == Keeping It Simple
#
# A \CSV object has dozens of instance methods that offer fine-grained control
# of parsing and generating \CSV data.
# For many needs, though, simpler approaches will do.
#
# This section summarizes the singleton methods in \CSV
# that allow you to parse and generate without explicitly
# creating \CSV objects.
# For details, follow the links.
#
# === Simple Parsing
#
# Parsing methods commonly return either of:
# - An \Array of Arrays of Strings:
# - The outer \Array is the entire "table".
# - Each inner \Array is a row.
# - Each \String is a field.
# - A CSV::Table object. For details, see
# {\CSV with Headers}[#class-CSV-label-CSV+with+Headers].
#
# ==== Parsing a \String
#
# The input to be parsed can be a string:
# string = "foo,0\nbar,1\nbaz,2\n"
#
# \Method CSV.parse returns the entire \CSV data:
# CSV.parse(string) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# \Method CSV.parse_line returns only the first row:
# CSV.parse_line(string) # => ["foo", "0"]
#
# \CSV extends class \String with instance method String#parse_csv,
# which also returns only the first row:
# string.parse_csv # => ["foo", "0"]
#
# ==== Parsing Via a \File Path
#
# The input to be parsed can be in a file:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# \Method CSV.read returns the entire \CSV data:
# CSV.read(path) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# \Method CSV.foreach iterates, passing each row to the given block:
# CSV.foreach(path) do |row|
# p row
# end
# Output:
# ["foo", "0"]
# ["bar", "1"]
# ["baz", "2"]
#
# \Method CSV.table returns the entire \CSV data as a CSV::Table object:
# CSV.table(path) # => #<CSV::Table mode:col_or_row row_count:3>
#
# ==== Parsing from an Open \IO Stream
#
# The input to be parsed can be in an open \IO stream:
#
# \Method CSV.read returns the entire \CSV data:
# File.open(path) do |file|
# CSV.read(file)
# end # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# As does method CSV.parse:
# File.open(path) do |file|
# CSV.parse(file)
# end # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# \Method CSV.parse_line returns only the first row:
# File.open(path) do |file|
# CSV.parse_line(file)
# end # => ["foo", "0"]
#
# \Method CSV.foreach iterates, passing each row to the given block:
# File.open(path) do |file|
# CSV.foreach(file) do |row|
# p row
# end
# end
# Output:
# ["foo", "0"]
# ["bar", "1"]
# ["baz", "2"]
#
# \Method CSV.table returns the entire \CSV data as a CSV::Table object:
# File.open(path) do |file|
# CSV.table(file)
# end # => #<CSV::Table mode:col_or_row row_count:3>
#
# === Simple Generating
#
# \Method CSV.generate returns a \String;
# this example uses method CSV#<< to append the rows
# that are to be generated:
# output_string = CSV.generate do |csv|
# csv << ['foo', 0]
# csv << ['bar', 1]
# csv << ['baz', 2]
# end
# output_string # => "foo,0\nbar,1\nbaz,2\n"
#
# \Method CSV.generate_line returns a \String containing the single row
# constructed from an \Array:
# CSV.generate_line(['foo', '0']) # => "foo,0\n"
#
# \CSV extends class \Array with instance method <tt>Array#to_csv</tt>,
# which forms an \Array into a \String:
# ['foo', '0'].to_csv # => "foo,0\n"
#
# === "Filtering" \CSV
#
# \Method CSV.filter provides a Unix-style filter for \CSV data.
# The input data is processed to form the output data:
# in_string = "foo,0\nbar,1\nbaz,2\n"
# out_string = ''
# CSV.filter(in_string, out_string) do |row|
# row[0] = row[0].upcase
# row[1] *= 4
# end
# out_string # => "FOO,0000\nBAR,1111\nBAZ,2222\n"
#
# == \CSV Objects
#
# There are three ways to create a \CSV object:
# - \Method CSV.new returns a new \CSV object.
# - \Method CSV.instance returns a new or cached \CSV object.
# - \Method \CSV() also returns a new or cached \CSV object.
#
# === Instance Methods
#
# \CSV has three groups of instance methods:
# - Its own internally defined instance methods.
# - Methods included by module Enumerable.
# - Methods delegated to class IO. See below.
#
# ==== Delegated Methods
#
# For convenience, a CSV object will delegate to many methods in class IO.
# (A few have wrapper "guard code" in \CSV.) You may call:
# * IO#binmode
# * #binmode?
# * IO#close
# * IO#close_read
# * IO#close_write
# * IO#closed?
# * #eof
# * #eof?
# * IO#external_encoding
# * IO#fcntl
# * IO#fileno
# * #flock
# * IO#flush
# * IO#fsync
# * IO#internal_encoding
# * #ioctl
# * IO#isatty
# * #path
# * IO#pid
# * IO#pos
# * IO#pos=
# * IO#reopen
# * #rewind
# * IO#seek
# * #stat
# * IO#string
# * IO#sync
# * IO#sync=
# * IO#tell
# * #to_i
# * #to_io
# * IO#truncate
# * IO#tty?
#
# === Options
#
# The default values for options are:
# DEFAULT_OPTIONS = {
# # For both parsing and generating.
# col_sep: ",",
# row_sep: :auto,
# quote_char: '"',
# # For parsing.
# field_size_limit: nil,
# converters: nil,
# unconverted_fields: nil,
# headers: false,
# return_headers: false,
# header_converters: nil,
# skip_blanks: false,
# skip_lines: nil,
# liberal_parsing: false,
# nil_value: nil,
# empty_value: "",
# strip: false,
# # For generating.
# write_headers: nil,
# quote_empty: true,
# force_quotes: false,
# write_converters: nil,
# write_nil_value: nil,
# write_empty_value: "",
# }
#
# ==== Options for Parsing
#
# Options for parsing, described in detail below, include:
# - +row_sep+: Specifies the row separator; used to delimit rows.
# - +col_sep+: Specifies the column separator; used to delimit fields.
# - +quote_char+: Specifies the quote character; used to quote fields.
# - +field_size_limit+: Specifies the maximum field size allowed.
# - +converters+: Specifies the field converters to be used.
# - +unconverted_fields+: Specifies whether unconverted fields are to be available.
# - +headers+: Specifies whether data contains headers,
# or specifies the headers themselves.
# - +return_headers+: Specifies whether headers are to be returned.
# - +header_converters+: Specifies the header converters to be used.
# - +skip_blanks+: Specifies whether blanks lines are to be ignored.
# - +skip_lines+: Specifies how comments lines are to be recognized.
# - +strip+: Specifies whether leading and trailing whitespace are to be
# stripped from fields. This must be compatible with +col_sep+; if it is not,
# then an +ArgumentError+ exception will be raised.
# - +liberal_parsing+: Specifies whether \CSV should attempt to parse
# non-compliant data.
# - +nil_value+: Specifies the object that is to be substituted for each null (no-text) field.
# - +empty_value+: Specifies the object that is to be substituted for each empty field.
#
# :include: ../doc/csv/options/common/row_sep.rdoc
#
# :include: ../doc/csv/options/common/col_sep.rdoc
#
# :include: ../doc/csv/options/common/quote_char.rdoc
#
# :include: ../doc/csv/options/parsing/field_size_limit.rdoc
#
# :include: ../doc/csv/options/parsing/converters.rdoc
#
# :include: ../doc/csv/options/parsing/unconverted_fields.rdoc
#
# :include: ../doc/csv/options/parsing/headers.rdoc
#
# :include: ../doc/csv/options/parsing/return_headers.rdoc
#
# :include: ../doc/csv/options/parsing/header_converters.rdoc
#
# :include: ../doc/csv/options/parsing/skip_blanks.rdoc
#
# :include: ../doc/csv/options/parsing/skip_lines.rdoc
#
# :include: ../doc/csv/options/parsing/strip.rdoc
#
# :include: ../doc/csv/options/parsing/liberal_parsing.rdoc
#
# :include: ../doc/csv/options/parsing/nil_value.rdoc
#
# :include: ../doc/csv/options/parsing/empty_value.rdoc
#
# ==== Options for Generating
#
# Options for generating, described in detail below, include:
# - +row_sep+: Specifies the row separator; used to delimit rows.
# - +col_sep+: Specifies the column separator; used to delimit fields.
# - +quote_char+: Specifies the quote character; used to quote fields.
# - +write_headers+: Specifies whether headers are to be written.
# - +force_quotes+: Specifies whether each output field is to be quoted.
# - +quote_empty+: Specifies whether each empty output field is to be quoted.
# - +write_converters+: Specifies the field converters to be used in writing.
# - +write_nil_value+: Specifies the object that is to be substituted for each +nil+-valued field.
# - +write_empty_value+: Specifies the object that is to be substituted for each empty field.
#
# :include: ../doc/csv/options/common/row_sep.rdoc
#
# :include: ../doc/csv/options/common/col_sep.rdoc
#
# :include: ../doc/csv/options/common/quote_char.rdoc
#
# :include: ../doc/csv/options/generating/write_headers.rdoc
#
# :include: ../doc/csv/options/generating/force_quotes.rdoc
#
# :include: ../doc/csv/options/generating/quote_empty.rdoc
#
# :include: ../doc/csv/options/generating/write_converters.rdoc
#
# :include: ../doc/csv/options/generating/write_nil_value.rdoc
#
# :include: ../doc/csv/options/generating/write_empty_value.rdoc
#
# === \CSV with Headers
#
# CSV allows to specify column names of CSV file, whether they are in data, or
# provided separately. If headers are specified, reading methods return an instance
# of CSV::Table, consisting of CSV::Row.
#
# # Headers are part of data
# data = CSV.parse(<<~ROWS, headers: true)
# Name,Department,Salary
# Bob,Engineering,1000
# Jane,Sales,2000
# John,Management,5000
# ROWS
#
# data.class #=> CSV::Table
# data.first #=> #<CSV::Row "Name":"Bob" "Department":"Engineering" "Salary":"1000">
# data.first.to_h #=> {"Name"=>"Bob", "Department"=>"Engineering", "Salary"=>"1000"}
#
# # Headers provided by developer
# data = CSV.parse('Bob,Engineering,1000', headers: %i[name department salary])
# data.first #=> #<CSV::Row name:"Bob" department:"Engineering" salary:"1000">
#
# === \Converters
#
# By default, each value (field or header) parsed by \CSV is formed into a \String.
# You can use a _field_ _converter_ or _header_ _converter_
# to intercept and modify the parsed values:
# - See {Field Converters}[#class-CSV-label-Field+Converters].
# - See {Header Converters}[#class-CSV-label-Header+Converters].
#
# Also by default, each value to be written during generation is written 'as-is'.
# You can use a _write_ _converter_ to modify values before writing.
# - See {Write Converters}[#class-CSV-label-Write+Converters].
#
# ==== Specifying \Converters
#
# You can specify converters for parsing or generating in the +options+
# argument to various \CSV methods:
# - Option +converters+ for converting parsed field values.
# - Option +header_converters+ for converting parsed header values.
# - Option +write_converters+ for converting values to be written (generated).
#
# There are three forms for specifying converters:
# - A converter proc: executable code to be used for conversion.
# - A converter name: the name of a stored converter.
# - A converter list: an array of converter procs, converter names, and converter lists.
#
# ===== Converter Procs
#
# This converter proc, +strip_converter+, accepts a value +field+
# and returns <tt>field.strip</tt>:
# strip_converter = proc {|field| field.strip }
# In this call to <tt>CSV.parse</tt>,
# the keyword argument <tt>converters: string_converter</tt>
# specifies that:
# - \Proc +string_converter+ is to be called for each parsed field.
# - The converter's return value is to replace the +field+ value.
# Example:
# string = " foo , 0 \n bar , 1 \n baz , 2 \n"
# array = CSV.parse(string, converters: strip_converter)
# array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# A converter proc can receive a second argument, +field_info+,
# that contains details about the field.
# This modified +strip_converter+ displays its arguments:
# strip_converter = proc do |field, field_info|
# p [field, field_info]
# field.strip
# end
# string = " foo , 0 \n bar , 1 \n baz , 2 \n"
# array = CSV.parse(string, converters: strip_converter)
# array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
# Output:
# [" foo ", #<struct CSV::FieldInfo index=0, line=1, header=nil>]
# [" 0 ", #<struct CSV::FieldInfo index=1, line=1, header=nil>]
# [" bar ", #<struct CSV::FieldInfo index=0, line=2, header=nil>]
# [" 1 ", #<struct CSV::FieldInfo index=1, line=2, header=nil>]
# [" baz ", #<struct CSV::FieldInfo index=0, line=3, header=nil>]
# [" 2 ", #<struct CSV::FieldInfo index=1, line=3, header=nil>]
# Each CSV::FieldInfo object shows:
# - The 0-based field index.
# - The 1-based line index.
# - The field header, if any.
#
# ===== Stored \Converters
#
# A converter may be given a name and stored in a structure where
# the parsing methods can find it by name.
#
# The storage structure for field converters is the \Hash CSV::Converters.
# It has several built-in converter procs:
# - <tt>:integer</tt>: converts each \String-embedded integer into a true \Integer.
# - <tt>:float</tt>: converts each \String-embedded float into a true \Float.
# - <tt>:date</tt>: converts each \String-embedded date into a true \Date.
# - <tt>:date_time</tt>: converts each \String-embedded date-time into a true \DateTime
# .
# This example creates a converter proc, then stores it:
# strip_converter = proc {|field| field.strip }
# CSV::Converters[:strip] = strip_converter
# Then the parsing method call can refer to the converter
# by its name, <tt>:strip</tt>:
# string = " foo , 0 \n bar , 1 \n baz , 2 \n"
# array = CSV.parse(string, converters: :strip)
# array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# The storage structure for header converters is the \Hash CSV::HeaderConverters,
# which works in the same way.
# It also has built-in converter procs:
# - <tt>:downcase</tt>: Downcases each header.
# - <tt>:symbol</tt>: Converts each header to a \Symbol.
#
# There is no such storage structure for write headers.
#
# In order for the parsing methods to access stored converters in non-main-Ractors, the
# storage structure must be made shareable first.
# Therefore, <tt>Ractor.make_shareable(CSV::Converters)</tt> and
# <tt>Ractor.make_shareable(CSV::HeaderConverters)</tt> must be called before the creation
# of Ractors that use the converters stored in these structures. (Since making the storage
# structures shareable involves freezing them, any custom converters that are to be used
# must be added first.)
#
# ===== Converter Lists
#
# A _converter_ _list_ is an \Array that may include any assortment of:
# - Converter procs.
# - Names of stored converters.
# - Nested converter lists.
#
# Examples:
# numeric_converters = [:integer, :float]
# date_converters = [:date, :date_time]
# [numeric_converters, strip_converter]
# [strip_converter, date_converters, :float]
#
# Like a converter proc, a converter list may be named and stored in either
# \CSV::Converters or CSV::HeaderConverters:
# CSV::Converters[:custom] = [strip_converter, date_converters, :float]
# CSV::HeaderConverters[:custom] = [:downcase, :symbol]
#
# There are two built-in converter lists:
# CSV::Converters[:numeric] # => [:integer, :float]
# CSV::Converters[:all] # => [:date_time, :numeric]
#
# ==== Field \Converters
#
# With no conversion, all parsed fields in all rows become Strings:
# string = "foo,0\nbar,1\nbaz,2\n"
# ary = CSV.parse(string)
# ary # => # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# When you specify a field converter, each parsed field is passed to the converter;
# its return value becomes the stored value for the field.
# A converter might, for example, convert an integer embedded in a \String
# into a true \Integer.
# (In fact, that's what built-in field converter +:integer+ does.)
#
# There are three ways to use field \converters.
#
# - Using option {converters}[#class-CSV-label-Option+converters] with a parsing method:
# ary = CSV.parse(string, converters: :integer)
# ary # => [0, 1, 2] # => [["foo", 0], ["bar", 1], ["baz", 2]]
# - Using option {converters}[#class-CSV-label-Option+converters] with a new \CSV instance:
# csv = CSV.new(string, converters: :integer)
# # Field converters in effect:
# csv.converters # => [:integer]
# csv.read # => [["foo", 0], ["bar", 1], ["baz", 2]]
# - Using method #convert to add a field converter to a \CSV instance:
# csv = CSV.new(string)
# # Add a converter.
# csv.convert(:integer)
# csv.converters # => [:integer]
# csv.read # => [["foo", 0], ["bar", 1], ["baz", 2]]
#
# Installing a field converter does not affect already-read rows:
# csv = CSV.new(string)
# csv.shift # => ["foo", "0"]
# # Add a converter.
# csv.convert(:integer)
# csv.converters # => [:integer]
# csv.read # => [["bar", 1], ["baz", 2]]
#
# There are additional built-in \converters, and custom \converters are also supported.
#
# ===== Built-In Field \Converters
#
# The built-in field converters are in \Hash CSV::Converters:
# - Each key is a field converter name.
# - Each value is one of:
# - A \Proc field converter.
# - An \Array of field converter names.
#
# Display:
# CSV::Converters.each_pair do |name, value|
# if value.kind_of?(Proc)
# p [name, value.class]
# else
# p [name, value]
# end
# end
# Output:
# [:integer, Proc]
# [:float, Proc]
# [:numeric, [:integer, :float]]
# [:date, Proc]
# [:date_time, Proc]
# [:all, [:date_time, :numeric]]
#
# Each of these converters transcodes values to UTF-8 before attempting conversion.
# If a value cannot be transcoded to UTF-8 the conversion will
# fail and the value will remain unconverted.
#
# Converter +:integer+ converts each field that Integer() accepts:
# data = '0,1,2,x'
# # Without the converter
# csv = CSV.parse_line(data)
# csv # => ["0", "1", "2", "x"]
# # With the converter
# csv = CSV.parse_line(data, converters: :integer)
# csv # => [0, 1, 2, "x"]
#
# Converter +:float+ converts each field that Float() accepts:
# data = '1.0,3.14159,x'
# # Without the converter
# csv = CSV.parse_line(data)
# csv # => ["1.0", "3.14159", "x"]
# # With the converter
# csv = CSV.parse_line(data, converters: :float)
# csv # => [1.0, 3.14159, "x"]
#
# Converter +:numeric+ converts with both +:integer+ and +:float+..
#
# Converter +:date+ converts each field that Date::parse accepts:
# data = '2001-02-03,x'
# # Without the converter
# csv = CSV.parse_line(data)
# csv # => ["2001-02-03", "x"]
# # With the converter
# csv = CSV.parse_line(data, converters: :date)
# csv # => [#<Date: 2001-02-03 ((2451944j,0s,0n),+0s,2299161j)>, "x"]
#
# Converter +:date_time+ converts each field that DateTime::parse accepts:
# data = '2020-05-07T14:59:00-05:00,x'
# # Without the converter
# csv = CSV.parse_line(data)
# csv # => ["2020-05-07T14:59:00-05:00", "x"]
# # With the converter
# csv = CSV.parse_line(data, converters: :date_time)
# csv # => [#<DateTime: 2020-05-07T14:59:00-05:00 ((2458977j,71940s,0n),-18000s,2299161j)>, "x"]
#
# Converter +:numeric+ converts with both +:date_time+ and +:numeric+..
#
# As seen above, method #convert adds \converters to a \CSV instance,
# and method #converters returns an \Array of the \converters in effect:
# csv = CSV.new('0,1,2')
# csv.converters # => []
# csv.convert(:integer)
# csv.converters # => [:integer]
# csv.convert(:date)
# csv.converters # => [:integer, :date]
#
# ===== Custom Field \Converters
#
# You can define a custom field converter:
# strip_converter = proc {|field| field.strip }
# string = " foo , 0 \n bar , 1 \n baz , 2 \n"
# array = CSV.parse(string, converters: strip_converter)
# array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
# You can register the converter in \Converters \Hash,
# which allows you to refer to it by name:
# CSV::Converters[:strip] = strip_converter
# string = " foo , 0 \n bar , 1 \n baz , 2 \n"
# array = CSV.parse(string, converters: :strip)
# array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# ==== Header \Converters
#
# Header converters operate only on headers (and not on other rows).
#
# There are three ways to use header \converters;
# these examples use built-in header converter +:dowhcase+,
# which downcases each parsed header.
#
# - Option +header_converters+ with a singleton parsing method:
# string = "Name,Count\nFoo,0\n,Bar,1\nBaz,2"
# tbl = CSV.parse(string, headers: true, header_converters: :downcase)
# tbl.class # => CSV::Table
# tbl.headers # => ["name", "count"]
#
# - Option +header_converters+ with a new \CSV instance:
# csv = CSV.new(string, header_converters: :downcase)
# # Header converters in effect:
# csv.header_converters # => [:downcase]
# tbl = CSV.parse(string, headers: true)
# tbl.headers # => ["Name", "Count"]
#
# - Method #header_convert adds a header converter to a \CSV instance:
# csv = CSV.new(string)
# # Add a header converter.
# csv.header_convert(:downcase)
# csv.header_converters # => [:downcase]
# tbl = CSV.parse(string, headers: true)
# tbl.headers # => ["Name", "Count"]
#
# ===== Built-In Header \Converters
#
# The built-in header \converters are in \Hash CSV::HeaderConverters.
# The keys there are the names of the \converters:
# CSV::HeaderConverters.keys # => [:downcase, :symbol]
#
# Converter +:downcase+ converts each header by downcasing it:
# string = "Name,Count\nFoo,0\n,Bar,1\nBaz,2"
# tbl = CSV.parse(string, headers: true, header_converters: :downcase)
# tbl.class # => CSV::Table
# tbl.headers # => ["name", "count"]
#
# Converter +:symbol+ converts each header by making it into a \Symbol:
# string = "Name,Count\nFoo,0\n,Bar,1\nBaz,2"
# tbl = CSV.parse(string, headers: true, header_converters: :symbol)
# tbl.headers # => [:name, :count]
# Details:
# - Strips leading and trailing whitespace.
# - Downcases the header.
# - Replaces embedded spaces with underscores.
# - Removes non-word characters.
# - Makes the string into a \Symbol.
#
# ===== Custom Header \Converters
#
# You can define a custom header converter:
# upcase_converter = proc {|header| header.upcase }
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(string, headers: true, header_converters: upcase_converter)
# table # => #<CSV::Table mode:col_or_row row_count:4>
# table.headers # => ["NAME", "VALUE"]
# You can register the converter in \HeaderConverters \Hash,
# which allows you to refer to it by name:
# CSV::HeaderConverters[:upcase] = upcase_converter
# table = CSV.parse(string, headers: true, header_converters: :upcase)
# table # => #<CSV::Table mode:col_or_row row_count:4>
# table.headers # => ["NAME", "VALUE"]
#
# ===== Write \Converters
#
# When you specify a write converter for generating \CSV,
# each field to be written is passed to the converter;
# its return value becomes the new value for the field.
# A converter might, for example, strip whitespace from a field.
#
# Using no write converter (all fields unmodified):
# output_string = CSV.generate do |csv|
# csv << [' foo ', 0]
# csv << [' bar ', 1]
# csv << [' baz ', 2]
# end
# output_string # => " foo ,0\n bar ,1\n baz ,2\n"
# Using option +write_converters+ with two custom write converters:
# strip_converter = proc {|field| field.respond_to?(:strip) ? field.strip : field }
# upcase_converter = proc {|field| field.respond_to?(:upcase) ? field.upcase : field }
# write_converters = [strip_converter, upcase_converter]
# output_string = CSV.generate(write_converters: write_converters) do |csv|
# csv << [' foo ', 0]
# csv << [' bar ', 1]
# csv << [' baz ', 2]
# end
# output_string # => "FOO,0\nBAR,1\nBAZ,2\n"
#
# === 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, <tt>:col_sep</tt>, <tt>:row_sep</tt>, and
# <tt>:quote_char</tt> 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(), CSV::open(),
# CSV::read(), and CSV::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 CSV::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}[mailto:james@grayproductions.net] any issues you
# find with it.
#
class CSV
# The error thrown when the parser encounters illegal CSV formatting.
class MalformedCSVError < RuntimeError
attr_reader :line_number
alias_method :lineno, :line_number
def initialize(message, line_number)
@line_number = line_number
super("#{message} in line #{line_number}.")
end
end
#
# 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.
#
# <b><tt>index</tt></b>:: The zero-based index of the field in its row.
# <b><tt>line</tt></b>:: The line of the data source this row is from.
# <b><tt>header</tt></b>:: The header for the column, when available.
#
FieldInfo = Struct.new(:index, :line, :header)
# A Regexp used to find and convert some common Date formats.
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 DateTime 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} |
# ISO-8601
\d{4}-\d{2}-\d{2}
(?:T\d{2}:\d{2}(?::\d{2}(?:\.\d+)?(?:[+-]\d{2}(?::\d{2})|Z)?)?)?
)\z /x
# The encoding used by all converters.
ConverterEncoding = Encoding.find("UTF-8")
# A \Hash containing the names and \Procs for the built-in field converters.
# See {Built-In Field Converters}[#class-CSV-label-Built-In+Field+Converters].
#
# This \Hash is intentionally left unfrozen, and may be extended with
# custom field converters.
# See {Custom Field Converters}[#class-CSV-label-Custom+Field+Converters].
Converters = {
integer: lambda { |f|
Integer(f.encode(ConverterEncoding)) rescue f
},
float: lambda { |f|
Float(f.encode(ConverterEncoding)) rescue f
},
numeric: [:integer, :float],
date: lambda { |f|
begin
e = f.encode(ConverterEncoding)
e.match?(DateMatcher) ? Date.parse(e) : f
rescue # encoding conversion or date parse errors
f
end
},
date_time: lambda { |f|
begin
e = f.encode(ConverterEncoding)
e.match?(DateTimeMatcher) ? DateTime.parse(e) : f
rescue # encoding conversion or date parse errors
f
end
},
all: [:date_time, :numeric],
}
# A \Hash containing the names and \Procs for the built-in header converters.
# See {Built-In Header Converters}[#class-CSV-label-Built-In+Header+Converters].
#
# This \Hash is intentionally left unfrozen, and may be extended with
# custom field converters.
# See {Custom Header Converters}[#class-CSV-label-Custom+Header+Converters].
HeaderConverters = {
downcase: lambda { |h| h.encode(ConverterEncoding).downcase },
symbol: lambda { |h|
h.encode(ConverterEncoding).downcase.gsub(/[^\s\w]+/, "").strip.
gsub(/\s+/, "_").to_sym
}
}
# Default values for method options.
DEFAULT_OPTIONS = {
# For both parsing and generating.
col_sep: ",",
row_sep: :auto,
quote_char: '"',
# For parsing.
field_size_limit: nil,
converters: nil,
unconverted_fields: nil,
headers: false,
return_headers: false,
header_converters: nil,
skip_blanks: false,
skip_lines: nil,
liberal_parsing: false,
nil_value: nil,
empty_value: "",
strip: false,
# For generating.
write_headers: nil,
quote_empty: true,
force_quotes: false,
write_converters: nil,
write_nil_value: nil,
write_empty_value: "",
}.freeze
class << self
# :call-seq:
# instance(string, **options)
# instance(io = $stdout, **options)
# instance(string, **options) {|csv| ... }
# instance(io = $stdout, **options) {|csv| ... }
#
# Creates or retrieves cached \CSV objects.
# For arguments and options, see CSV.new.
#
# This API is not Ractor-safe.
#
# ---
#
# With no block given, returns a \CSV object.
#
# The first call to +instance+ creates and caches a \CSV object:
# s0 = 's0'
# csv0 = CSV.instance(s0)
# csv0.class # => CSV
#
# Subsequent calls to +instance+ with that _same_ +string+ or +io+
# retrieve that same cached object:
# csv1 = CSV.instance(s0)
# csv1.class # => CSV
# csv1.equal?(csv0) # => true # Same CSV object
#
# A subsequent call to +instance+ with a _different_ +string+ or +io+
# creates and caches a _different_ \CSV object.
# s1 = 's1'
# csv2 = CSV.instance(s1)
# csv2.equal?(csv0) # => false # Different CSV object
#
# All the cached objects remains available:
# csv3 = CSV.instance(s0)
# csv3.equal?(csv0) # true # Same CSV object
# csv4 = CSV.instance(s1)
# csv4.equal?(csv2) # true # Same CSV object
#
# ---
#
# When a block is given, calls the block with the created or retrieved
# \CSV object; returns the block's return value:
# CSV.instance(s0) {|csv| :foo } # => :foo
def instance(data = $stdout, **options)
# create a _signature_ for this method call, data object and options
sig = [data.object_id] +
options.values_at(*DEFAULT_OPTIONS.keys.sort_by { |sym| sym.to_s })
# fetch or create the instance for this signature
@@instances ||= Hash.new
instance = (@@instances[sig] ||= new(data, **options))
if block_given?
yield instance # run block, if given, returning result
else
instance # or return the instance
end
end
# :call-seq:
# filter(**options) {|row| ... }
# filter(in_string, **options) {|row| ... }
# filter(in_io, **options) {|row| ... }
# filter(in_string, out_string, **options) {|row| ... }
# filter(in_string, out_io, **options) {|row| ... }
# filter(in_io, out_string, **options) {|row| ... }
# filter(in_io, out_io, **options) {|row| ... }
#
# Reads \CSV input and writes \CSV output.
#
# For each input row:
# - Forms the data into:
# - A CSV::Row object, if headers are in use.
# - An \Array of Arrays, otherwise.
# - Calls the block with that object.
# - Appends the block's return value to the output.
#
# Arguments:
# * \CSV source:
# * Argument +in_string+, if given, should be a \String object;
# it will be put into a new StringIO object positioned at the beginning.
# * Argument +in_io+, if given, should be an IO object that is
# open for reading; on return, the IO object will be closed.
# * If neither +in_string+ nor +in_io+ is given,
# the input stream defaults to {ARGF}[https://ruby-doc.org/core/ARGF.html].
# * \CSV output:
# * Argument +out_string+, if given, should be a \String object;
# it will be put into a new StringIO object positioned at the beginning.
# * Argument +out_io+, if given, should be an IO object that is
# ppen for writing; on return, the IO object will be closed.
# * If neither +out_string+ nor +out_io+ is given,
# the output stream defaults to <tt>$stdout</tt>.
# * Argument +options+ should be keyword arguments.
# - Each argument name that is prefixed with +in_+ or +input_+
# is stripped of its prefix and is treated as an option
# for parsing the input.
# Option +input_row_sep+ defaults to <tt>$INPUT_RECORD_SEPARATOR</tt>.
# - Each argument name that is prefixed with +out_+ or +output_+
# is stripped of its prefix and is treated as an option
# for generating the output.
# Option +output_row_sep+ defaults to <tt>$INPUT_RECORD_SEPARATOR</tt>.
# - Each argument not prefixed as above is treated as an option
# both for parsing the input and for generating the output.
# - See {Options for Parsing}[#class-CSV-label-Options+for+Parsing]
# and {Options for Generating}[#class-CSV-label-Options+for+Generating].
#
# Example:
# in_string = "foo,0\nbar,1\nbaz,2\n"
# out_string = ''
# CSV.filter(in_string, out_string) do |row|
# row[0] = row[0].upcase
# row[1] *= 4
# end
# out_string # => "FOO,0000\nBAR,1111\nBAZ,2222\n"
def filter(input=nil, output=nil, **options)
# parse options for input, output, or both
in_options, out_options = Hash.new, {row_sep: InputRecordSeparator.value}
options.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
# build input and output wrappers
input = new(input || ARGF, **in_options)
output = new(output || $stdout, **out_options)
# process headers
need_manual_header_output =
(in_options[:headers] and
out_options[:headers] == true and
out_options[:write_headers])
if need_manual_header_output
first_row = input.shift
if first_row
if first_row.is_a?(Row)
headers = first_row.headers
yield headers
output << headers
end
yield first_row
output << first_row
end
end
# read, yield, write
input.each do |row|
yield row
output << row
end
end
#
# :call-seq:
# foreach(path, mode='r', **options) {|row| ... )
# foreach(io, mode='r', **options {|row| ... )
# foreach(path, mode='r', headers: ..., **options) {|row| ... )
# foreach(io, mode='r', headers: ..., **options {|row| ... )
# foreach(path, mode='r', **options) -> new_enumerator
# foreach(io, mode='r', **options -> new_enumerator
#
# Calls the block with each row read from source +path+ or +io+.
#
# * Argument +path+, if given, must be the path to a file.
# :include: ../doc/csv/arguments/io.rdoc
# * Argument +mode+, if given, must be a \File mode
# See {Open Mode}[IO.html#method-c-new-label-Open+Mode].
# * Arguments <tt>**options</tt> must be keyword options.
# See {Options for Parsing}[#class-CSV-label-Options+for+Parsing].
# * This method optionally accepts an additional <tt>:encoding</tt> option
# that you can use to specify the Encoding of the data read from +path+ or +io+.
# You must provide this unless your data is in the encoding
# given by <tt>Encoding::default_external</tt>.
# Parsing 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 parsing.
#
# ====== Without Option +headers+
#
# Without option +headers+, returns each row as an \Array object.
#
# These examples assume prior execution of:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# Read rows from a file at +path+:
# CSV.foreach(path) {|row| p row }
# Output:
# ["foo", "0"]
# ["bar", "1"]
# ["baz", "2"]
#
# Read rows from an \IO object:
# File.open(path) do |file|
# CSV.foreach(file) {|row| p row }
# end
#
# Output:
# ["foo", "0"]
# ["bar", "1"]
# ["baz", "2"]
#
# Returns a new \Enumerator if no block given:
# CSV.foreach(path) # => #<Enumerator: CSV:foreach("t.csv", "r")>
# CSV.foreach(File.open(path)) # => #<Enumerator: CSV:foreach(#<File:t.csv>, "r")>
#
# Issues a warning if an encoding is unsupported:
# CSV.foreach(File.open(path), encoding: 'foo:bar') {|row| }
# Output:
# warning: Unsupported encoding foo ignored
# warning: Unsupported encoding bar ignored
#
# ====== With Option +headers+
#
# With {option +headers+}[#class-CSV-label-Option+headers],
# returns each row as a CSV::Row object.
#
# These examples assume prior execution of:
# string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# Read rows from a file at +path+:
# CSV.foreach(path, headers: true) {|row| p row }
#
# Output:
# #<CSV::Row "Name":"foo" "Count":"0">
# #<CSV::Row "Name":"bar" "Count":"1">
# #<CSV::Row "Name":"baz" "Count":"2">
#
# Read rows from an \IO object:
# File.open(path) do |file|
# CSV.foreach(file, headers: true) {|row| p row }
# end
#
# Output:
# #<CSV::Row "Name":"foo" "Count":"0">
# #<CSV::Row "Name":"bar" "Count":"1">
# #<CSV::Row "Name":"baz" "Count":"2">
#
# ---
#
# Raises an exception if +path+ is a \String, but not the path to a readable file:
# # Raises Errno::ENOENT (No such file or directory @ rb_sysopen - nosuch.csv):
# CSV.foreach('nosuch.csv') {|row| }
#
# Raises an exception if +io+ is an \IO object, but not open for reading:
# io = File.open(path, 'w') {|row| }
# # Raises TypeError (no implicit conversion of nil into String):
# CSV.foreach(io) {|row| }
#
# Raises an exception if +mode+ is invalid:
# # Raises ArgumentError (invalid access mode nosuch):
# CSV.foreach(path, 'nosuch') {|row| }
#
def foreach(path, mode="r", **options, &block)
return to_enum(__method__, path, mode, **options) unless block_given?
open(path, mode, **options) do |csv|
csv.each(&block)
end
end
#
# :call-seq:
# generate(csv_string, **options) {|csv| ... }
# generate(**options) {|csv| ... }
#
# * Argument +csv_string+, if given, must be a \String object;
# defaults to a new empty \String.
# * Arguments +options+, if given, should be generating options.
# See {Options for Generating}[#class-CSV-label-Options+for+Generating].
#
# ---
#
# Creates a new \CSV object via <tt>CSV.new(csv_string, **options)</tt>;
# calls the block with the \CSV object, which the block may modify;
# returns the \String generated from the \CSV object.
#
# Note that a passed \String *is* modified by this method.
# Pass <tt>csv_string</tt>.dup if the \String must be preserved.
#
# This method has one additional option: <tt>:encoding</tt>,
# which sets the base Encoding for the output if no no +str+ is specified.
# CSV needs this hint if you plan to output non-ASCII compatible data.
#
# ---
#
# Add lines:
# input_string = "foo,0\nbar,1\nbaz,2\n"
# output_string = CSV.generate(input_string) do |csv|
# csv << ['bat', 3]
# csv << ['bam', 4]
# end
# output_string # => "foo,0\nbar,1\nbaz,2\nbat,3\nbam,4\n"
# input_string # => "foo,0\nbar,1\nbaz,2\nbat,3\nbam,4\n"
# output_string.equal?(input_string) # => true # Same string, modified
#
# Add lines into new string, preserving old string:
# input_string = "foo,0\nbar,1\nbaz,2\n"
# output_string = CSV.generate(input_string.dup) do |csv|
# csv << ['bat', 3]
# csv << ['bam', 4]
# end
# output_string # => "foo,0\nbar,1\nbaz,2\nbat,3\nbam,4\n"
# input_string # => "foo,0\nbar,1\nbaz,2\n"
# output_string.equal?(input_string) # => false # Different strings
#
# Create lines from nothing:
# output_string = CSV.generate do |csv|
# csv << ['foo', 0]
# csv << ['bar', 1]
# csv << ['baz', 2]
# end
# output_string # => "foo,0\nbar,1\nbaz,2\n"
#
# ---
#
# Raises an exception if +csv_string+ is not a \String object:
# # Raises TypeError (no implicit conversion of Integer into String)
# CSV.generate(0)
#
def generate(str=nil, **options)
encoding = options[:encoding]
# add a default empty String, if none was given
if str
str = StringIO.new(str)
str.seek(0, IO::SEEK_END)
str.set_encoding(encoding) if encoding
else
str = +""
str.force_encoding(encoding) if encoding
end
csv = new(str, **options) # wrap
yield csv # yield for appending
csv.string # return final String
end
# :call-seq:
# CSV.generate_line(ary)
# CSV.generate_line(ary, **options)
#
# Returns the \String created by generating \CSV from +ary+
# using the specified +options+.
#
# Argument +ary+ must be an \Array.
#
# Special options:
# * Option <tt>:row_sep</tt> defaults to <tt>"\n"> on Ruby 3.0 or later
# and <tt>$INPUT_RECORD_SEPARATOR</tt> (<tt>$/</tt>) otherwise.:
# $INPUT_RECORD_SEPARATOR # => "\n"
# * This method accepts an additional option, <tt>:encoding</tt>, which sets 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.
#
# For other +options+,
# see {Options for Generating}[#class-CSV-label-Options+for+Generating].
#
# ---
#
# Returns the \String generated from an \Array:
# CSV.generate_line(['foo', '0']) # => "foo,0\n"
#
# ---
#
# Raises an exception if +ary+ is not an \Array:
# # Raises NoMethodError (undefined method `find' for :foo:Symbol)
# CSV.generate_line(:foo)
#
def generate_line(row, **options)
options = {row_sep: InputRecordSeparator.value}.merge(options)
str = +""
if options[:encoding]
str.force_encoding(options[:encoding])
else
fallback_encoding = nil
output_encoding = nil
row.each do |field|
next unless field.is_a?(String)
fallback_encoding ||= field.encoding
next if field.ascii_only?
output_encoding = field.encoding
break
end
output_encoding ||= fallback_encoding
if output_encoding
str.force_encoding(output_encoding)
end
end
(new(str, **options) << row).string
end
#
# :call-seq:
# open(file_path, mode = "rb", **options ) -> new_csv
# open(io, mode = "rb", **options ) -> new_csv
# open(file_path, mode = "rb", **options ) { |csv| ... } -> object
# open(io, mode = "rb", **options ) { |csv| ... } -> object
#
# possible options elements:
# hash form:
# :invalid => nil # raise error on invalid byte sequence (default)
# :invalid => :replace # replace invalid byte sequence
# :undef => :replace # replace undefined conversion
# :replace => string # replacement string ("?" or "\uFFFD" if not specified)
#
# * Argument +path+, if given, must be the path to a file.
# :include: ../doc/csv/arguments/io.rdoc
# * Argument +mode+, if given, must be a \File mode
# See {Open Mode}[IO.html#method-c-new-label-Open+Mode].
# * Arguments <tt>**options</tt> must be keyword options.
# See {Options for Generating}[#class-CSV-label-Options+for+Generating].
# * This method optionally accepts an additional <tt>:encoding</tt> option
# that you can use to specify the Encoding of the data read from +path+ or +io+.
# You must provide this unless your data is in the encoding
# given by <tt>Encoding::default_external</tt>.
# Parsing 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 parsing.
#
# ---
#
# These examples assume prior execution of:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# ---
#
# With no block given, returns a new \CSV object.
#
# Create a \CSV object using a file path:
# csv = CSV.open(path)
# csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
#
# Create a \CSV object using an open \File:
# csv = CSV.open(File.open(path))
# csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
#
# ---
#
# With a block given, calls the block with the created \CSV object;
# returns the block's return value:
#
# Using a file path:
# csv = CSV.open(path) {|csv| p csv}
# csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
# Output:
# #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
#
# Using an open \File:
# csv = CSV.open(File.open(path)) {|csv| p csv}
# csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
# Output:
# #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
#
# ---
#
# Raises an exception if the argument is not a \String object or \IO object:
# # Raises TypeError (no implicit conversion of Symbol into String)
# CSV.open(:foo)
def open(filename, mode="r", **options)
# wrap a File opened with the remaining +args+ with no newline
# decorator
file_opts = {universal_newline: false}.merge(options)
options.delete(:invalid)
options.delete(:undef)
options.delete(:replace)
begin
f = File.open(filename, mode, **file_opts)
rescue ArgumentError => e
raise unless /needs binmode/.match?(e.message) and mode == "r"
mode = "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
#
# :call-seq:
# parse(string) -> array_of_arrays
# parse(io) -> array_of_arrays
# parse(string, headers: ..., **options) -> csv_table
# parse(io, headers: ..., **options) -> csv_table
# parse(string, **options) {|row| ... }
# parse(io, **options) {|row| ... }
#
# Parses +string+ or +io+ using the specified +options+.
#
# - Argument +string+ should be a \String object;
# it will be put into a new StringIO object positioned at the beginning.
# :include: ../doc/csv/arguments/io.rdoc
# - Argument +options+: see {Options for Parsing}[#class-CSV-label-Options+for+Parsing]
#
# ====== Without Option +headers+
#
# Without {option +headers+}[#class-CSV-label-Option+headers] case.
#
# These examples assume prior execution of:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# ---
#
# With no block given, returns an \Array of Arrays formed from the source.
#
# Parse a \String:
# a_of_a = CSV.parse(string)
# a_of_a # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# Parse an open \File:
# a_of_a = File.open(path) do |file|
# CSV.parse(file)
# end
# a_of_a # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# ---
#
# With a block given, calls the block with each parsed row:
#
# Parse a \String:
# CSV.parse(string) {|row| p row }
#
# Output:
# ["foo", "0"]
# ["bar", "1"]
# ["baz", "2"]
#
# Parse an open \File:
# File.open(path) do |file|
# CSV.parse(file) {|row| p row }
# end
#
# Output:
# ["foo", "0"]
# ["bar", "1"]
# ["baz", "2"]
#
# ====== With Option +headers+
#
# With {option +headers+}[#class-CSV-label-Option+headers] case.
#
# These examples assume prior execution of:
# string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# ---
#
# With no block given, returns a CSV::Table object formed from the source.
#
# Parse a \String:
# csv_table = CSV.parse(string, headers: ['Name', 'Count'])
# csv_table # => #<CSV::Table mode:col_or_row row_count:5>
#
# Parse an open \File:
# csv_table = File.open(path) do |file|
# CSV.parse(file, headers: ['Name', 'Count'])
# end
# csv_table # => #<CSV::Table mode:col_or_row row_count:4>
#
# ---
#
# With a block given, calls the block with each parsed row,
# which has been formed into a CSV::Row object:
#
# Parse a \String:
# CSV.parse(string, headers: ['Name', 'Count']) {|row| p row }
#
# Output:
# # <CSV::Row "Name":"foo" "Count":"0">
# # <CSV::Row "Name":"bar" "Count":"1">
# # <CSV::Row "Name":"baz" "Count":"2">
#
# Parse an open \File:
# File.open(path) do |file|
# CSV.parse(file, headers: ['Name', 'Count']) {|row| p row }
# end
#
# Output:
# # <CSV::Row "Name":"foo" "Count":"0">
# # <CSV::Row "Name":"bar" "Count":"1">
# # <CSV::Row "Name":"baz" "Count":"2">
#
# ---
#
# Raises an exception if the argument is not a \String object or \IO object:
# # Raises NoMethodError (undefined method `close' for :foo:Symbol)
# CSV.parse(:foo)
def parse(str, **options, &block)
csv = new(str, **options)
return csv.each(&block) if block_given?
# slurp contents, if no block is given
begin
csv.read
ensure
csv.close
end
end
# :call-seq:
# CSV.parse_line(string) -> new_array or nil
# CSV.parse_line(io) -> new_array or nil
# CSV.parse_line(string, **options) -> new_array or nil
# CSV.parse_line(io, **options) -> new_array or nil
# CSV.parse_line(string, headers: true, **options) -> csv_row or nil
# CSV.parse_line(io, headers: true, **options) -> csv_row or nil
#
# Returns the data created by parsing the first line of +string+ or +io+
# using the specified +options+.
#
# - Argument +string+ should be a \String object;
# it will be put into a new StringIO object positioned at the beginning.
# :include: ../doc/csv/arguments/io.rdoc
# - Argument +options+: see {Options for Parsing}[#class-CSV-label-Options+for+Parsing]
#
# ====== Without Option +headers+
#
# Without option +headers+, returns the first row as a new \Array.
#
# These examples assume prior execution of:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# Parse the first line from a \String object:
# CSV.parse_line(string) # => ["foo", "0"]
#
# Parse the first line from a File object:
# File.open(path) do |file|
# CSV.parse_line(file) # => ["foo", "0"]
# end # => ["foo", "0"]
#
# Returns +nil+ if the argument is an empty \String:
# CSV.parse_line('') # => nil
#
# ====== With Option +headers+
#
# With {option +headers+}[#class-CSV-label-Option+headers],
# returns the first row as a CSV::Row object.
#
# These examples assume prior execution of:
# string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# Parse the first line from a \String object:
# CSV.parse_line(string, headers: true) # => #<CSV::Row "Name":"foo" "Count":"0">
#
# Parse the first line from a File object:
# File.open(path) do |file|
# CSV.parse_line(file, headers: true)
# end # => #<CSV::Row "Name":"foo" "Count":"0">
#
# ---
#
# Raises an exception if the argument is +nil+:
# # Raises ArgumentError (Cannot parse nil as CSV):
# CSV.parse_line(nil)
#
def parse_line(line, **options)
new(line, **options).each.first
end
#
# :call-seq:
# read(source, **options) -> array_of_arrays
# read(source, headers: true, **options) -> csv_table
#
# Opens the given +source+ with the given +options+ (see CSV.open),
# reads the source (see CSV#read), and returns the result,
# which will be either an \Array of Arrays or a CSV::Table.
#
# Without headers:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
# CSV.read(path) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# With headers:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
# CSV.read(path, headers: true) # => #<CSV::Table mode:col_or_row row_count:4>
def read(path, **options)
open(path, **options) { |csv| csv.read }
end
# :call-seq:
# CSV.readlines(source, **options)
#
# Alias for CSV.read.
def readlines(path, **options)
read(path, **options)
end
# :call-seq:
# CSV.table(source, **options)
#
# Calls CSV.read with +source+, +options+, and certain default options:
# - +headers+: +true+
# - +converters+: +:numeric+
# - +header_converters+: +:symbol+
#
# Returns a CSV::Table object.
#
# Example:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
# CSV.table(path) # => #<CSV::Table mode:col_or_row row_count:4>
def table(path, **options)
default_options = {
headers: true,
converters: :numeric,
header_converters: :symbol,
}
options = default_options.merge(options)
read(path, **options)
end
end
# :call-seq:
# CSV.new(string)
# CSV.new(io)
# CSV.new(string, **options)
# CSV.new(io, **options)
#
# Returns the new \CSV object created using +string+ or +io+
# and the specified +options+.
#
# - Argument +string+ should be a \String object;
# it will be put into a new StringIO object positioned at the beginning.
# :include: ../doc/csv/arguments/io.rdoc
# - Argument +options+: See:
# * {Options for Parsing}[#class-CSV-label-Options+for+Parsing]
# * {Options for Generating}[#class-CSV-label-Options+for+Generating]
# For performance reasons, the options cannot be overridden
# in a \CSV object, so those specified here will endure.
#
# In addition to the \CSV instance methods, several \IO methods are delegated.
# See {Delegated Methods}[#class-CSV-label-Delegated+Methods].
#
# ---
#
# Create a \CSV object from a \String object:
# csv = CSV.new('foo,0')
# csv # => #<CSV io_type:StringIO encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
#
# Create a \CSV object from a \File object:
# File.write('t.csv', 'foo,0')
# csv = CSV.new(File.open('t.csv'))
# csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
#
# ---
#
# Raises an exception if the argument is +nil+:
# # Raises ArgumentError (Cannot parse nil as CSV):
# CSV.new(nil)
#
def initialize(data,
col_sep: ",",
row_sep: :auto,
quote_char: '"',
field_size_limit: nil,
converters: nil,
unconverted_fields: nil,
headers: false,
return_headers: false,
write_headers: nil,
header_converters: nil,
skip_blanks: false,
force_quotes: false,
skip_lines: nil,
liberal_parsing: false,
internal_encoding: nil,
external_encoding: nil,
encoding: nil,
nil_value: nil,
empty_value: "",
strip: false,
quote_empty: true,
write_converters: nil,
write_nil_value: nil,
write_empty_value: "")
raise ArgumentError.new("Cannot parse nil as CSV") if data.nil?
if data.is_a?(String)
@io = StringIO.new(data)
@io.set_encoding(encoding || data.encoding)
else
@io = data
end
@encoding = determine_encoding(encoding, internal_encoding)
@base_fields_converter_options = {
nil_value: nil_value,
empty_value: empty_value,
}
@write_fields_converter_options = {
nil_value: write_nil_value,
empty_value: write_empty_value,
}
@initial_converters = converters
@initial_header_converters = header_converters
@initial_write_converters = write_converters
@parser_options = {
column_separator: col_sep,
row_separator: row_sep,
quote_character: quote_char,
field_size_limit: field_size_limit,
unconverted_fields: unconverted_fields,
headers: headers,
return_headers: return_headers,
skip_blanks: skip_blanks,
skip_lines: skip_lines,
liberal_parsing: liberal_parsing,
encoding: @encoding,
nil_value: nil_value,
empty_value: empty_value,
strip: strip,
}
@parser = nil
@parser_enumerator = nil
@eof_error = nil
@writer_options = {
encoding: @encoding,
force_encoding: (not encoding.nil?),
force_quotes: force_quotes,
headers: headers,
write_headers: write_headers,
column_separator: col_sep,
row_separator: row_sep,
quote_character: quote_char,
quote_empty: quote_empty,
}
@writer = nil
writer if @writer_options[:write_headers]
end
# :call-seq:
# csv.col_sep -> string
#
# Returns the encoded column separator; used for parsing and writing;
# see {Option +col_sep+}[#class-CSV-label-Option+col_sep]:
# CSV.new('').col_sep # => ","
def col_sep
parser.column_separator
end
# :call-seq:
# csv.row_sep -> string
#
# Returns the encoded row separator; used for parsing and writing;
# see {Option +row_sep+}[#class-CSV-label-Option+row_sep]:
# CSV.new('').row_sep # => "\n"
def row_sep
parser.row_separator
end
# :call-seq:
# csv.quote_char -> character
#
# Returns the encoded quote character; used for parsing and writing;
# see {Option +quote_char+}[#class-CSV-label-Option+quote_char]:
# CSV.new('').quote_char # => "\""
def quote_char
parser.quote_character
end
# :call-seq:
# csv.field_size_limit -> integer or nil
#
# Returns the limit for field size; used for parsing;
# see {Option +field_size_limit+}[#class-CSV-label-Option+field_size_limit]:
# CSV.new('').field_size_limit # => nil
def field_size_limit
parser.field_size_limit
end
# :call-seq:
# csv.skip_lines -> regexp or nil
#
# Returns the \Regexp used to identify comment lines; used for parsing;
# see {Option +skip_lines+}[#class-CSV-label-Option+skip_lines]:
# CSV.new('').skip_lines # => nil
def skip_lines
parser.skip_lines
end
# :call-seq:
# csv.converters -> array
#
# Returns an \Array containing field converters;
# see {Field Converters}[#class-CSV-label-Field+Converters]:
# csv = CSV.new('')
# csv.converters # => []
# csv.convert(:integer)
# csv.converters # => [:integer]
# csv.convert(proc {|x| x.to_s })
# csv.converters
#
# Notes that you need to call
# +Ractor.make_shareable(CSV::Converters)+ on the main Ractor to use
# this method.
def converters
parser_fields_converter.map do |converter|
name = Converters.rassoc(converter)
name ? name.first : converter
end
end
# :call-seq:
# csv.unconverted_fields? -> object
#
# Returns the value that determines whether unconverted fields are to be
# available; used for parsing;
# see {Option +unconverted_fields+}[#class-CSV-label-Option+unconverted_fields]:
# CSV.new('').unconverted_fields? # => nil
def unconverted_fields?
parser.unconverted_fields?
end
# :call-seq:
# csv.headers -> object
#
# Returns the value that determines whether headers are used; used for parsing;
# see {Option +headers+}[#class-CSV-label-Option+headers]:
# CSV.new('').headers # => nil
def headers
if @writer
@writer.headers
else
parsed_headers = parser.headers
return parsed_headers if parsed_headers
raw_headers = @parser_options[:headers]
raw_headers = nil if raw_headers == false
raw_headers
end
end
# :call-seq:
# csv.return_headers? -> true or false
#
# Returns the value that determines whether headers are to be returned; used for parsing;
# see {Option +return_headers+}[#class-CSV-label-Option+return_headers]:
# CSV.new('').return_headers? # => false
def return_headers?
parser.return_headers?
end
# :call-seq:
# csv.write_headers? -> true or false
#
# Returns the value that determines whether headers are to be written; used for generating;
# see {Option +write_headers+}[#class-CSV-label-Option+write_headers]:
# CSV.new('').write_headers? # => nil
def write_headers?
@writer_options[:write_headers]
end
# :call-seq:
# csv.header_converters -> array
#
# Returns an \Array containing header converters; used for parsing;
# see {Header Converters}[#class-CSV-label-Header+Converters]:
# CSV.new('').header_converters # => []
#
# Notes that you need to call
# +Ractor.make_shareable(CSV::HeaderConverters)+ on the main Ractor
# to use this method.
def header_converters
header_fields_converter.map do |converter|
name = HeaderConverters.rassoc(converter)
name ? name.first : converter
end
end
# :call-seq:
# csv.skip_blanks? -> true or false
#
# Returns the value that determines whether blank lines are to be ignored; used for parsing;
# see {Option +skip_blanks+}[#class-CSV-label-Option+skip_blanks]:
# CSV.new('').skip_blanks? # => false
def skip_blanks?
parser.skip_blanks?
end
# :call-seq:
# csv.force_quotes? -> true or false
#
# Returns the value that determines whether all output fields are to be quoted;
# used for generating;
# see {Option +force_quotes+}[#class-CSV-label-Option+force_quotes]:
# CSV.new('').force_quotes? # => false
def force_quotes?
@writer_options[:force_quotes]
end
# :call-seq:
# csv.liberal_parsing? -> true or false
#
# Returns the value that determines whether illegal input is to be handled; used for parsing;
# see {Option +liberal_parsing+}[#class-CSV-label-Option+liberal_parsing]:
# CSV.new('').liberal_parsing? # => false
def liberal_parsing?
parser.liberal_parsing?
end
# :call-seq:
# csv.encoding -> endcoding
#
# Returns the encoding used for parsing and generating;
# see {Character Encodings (M17n or Multilingualization)}[#class-CSV-label-Character+Encodings+-28M17n+or+Multilingualization-29]:
# CSV.new('').encoding # => #<Encoding:UTF-8>
attr_reader :encoding
# :call-seq:
# csv.line_no -> integer
#
# Returns the count of the rows parsed or generated.
#
# Parsing:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
# CSV.open(path) do |csv|
# csv.each do |row|
# p [csv.lineno, row]
# end
# end
# Output:
# [1, ["foo", "0"]]
# [2, ["bar", "1"]]
# [3, ["baz", "2"]]
#
# Generating:
# CSV.generate do |csv|
# p csv.lineno; csv << ['foo', 0]
# p csv.lineno; csv << ['bar', 1]
# p csv.lineno; csv << ['baz', 2]
# end
# Output:
# 0
# 1
# 2
def lineno
if @writer
@writer.lineno
else
parser.lineno
end
end
# :call-seq:
# csv.line -> array
#
# Returns the line most recently read:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
# CSV.open(path) do |csv|
# csv.each do |row|
# p [csv.lineno, csv.line]
# end
# end
# Output:
# [1, "foo,0\n"]
# [2, "bar,1\n"]
# [3, "baz,2\n"]
def line
parser.line
end
### IO and StringIO Delegation ###
extend Forwardable
def_delegators :@io, :binmode, :close, :close_read, :close_write,
:closed?, :external_encoding, :fcntl,
:fileno, :flush, :fsync, :internal_encoding,
:isatty, :pid, :pos, :pos=, :reopen,
:seek, :string, :sync, :sync=, :tell,
:truncate, :tty?
def binmode?
if @io.respond_to?(:binmode?)
@io.binmode?
else
false
end
end
def flock(*args)
raise NotImplementedError unless @io.respond_to?(:flock)
@io.flock(*args)
end
def ioctl(*args)
raise NotImplementedError unless @io.respond_to?(:ioctl)
@io.ioctl(*args)
end
def path
@io.path if @io.respond_to?(:path)
end
def stat(*args)
raise NotImplementedError unless @io.respond_to?(:stat)
@io.stat(*args)
end
def to_i
raise NotImplementedError unless @io.respond_to?(:to_i)
@io.to_i
end
def to_io
@io.respond_to?(:to_io) ? @io.to_io : @io
end
def eof?
return false if @eof_error
begin
parser_enumerator.peek
false
rescue MalformedCSVError => error
@eof_error = error
false
rescue StopIteration
true
end
end
alias_method :eof, :eof?
# Rewinds the underlying IO object and resets CSV's lineno() counter.
def rewind
@parser = nil
@parser_enumerator = nil
@eof_error = nil
@writer.rewind if @writer
@io.rewind
end
### End Delegation ###
# :call-seq:
# csv << row -> self
#
# Appends a row to +self+.
#
# - Argument +row+ must be an \Array object or a CSV::Row object.
# - The output stream must be open for writing.
#
# ---
#
# Append Arrays:
# CSV.generate do |csv|
# csv << ['foo', 0]
# csv << ['bar', 1]
# csv << ['baz', 2]
# end # => "foo,0\nbar,1\nbaz,2\n"
#
# Append CSV::Rows:
# headers = []
# CSV.generate do |csv|
# csv << CSV::Row.new(headers, ['foo', 0])
# csv << CSV::Row.new(headers, ['bar', 1])
# csv << CSV::Row.new(headers, ['baz', 2])
# end # => "foo,0\nbar,1\nbaz,2\n"
#
# Headers in CSV::Row objects are not appended:
# headers = ['Name', 'Count']
# CSV.generate do |csv|
# csv << CSV::Row.new(headers, ['foo', 0])
# csv << CSV::Row.new(headers, ['bar', 1])
# csv << CSV::Row.new(headers, ['baz', 2])
# end # => "foo,0\nbar,1\nbaz,2\n"
#
# ---
#
# Raises an exception if +row+ is not an \Array or \CSV::Row:
# CSV.generate do |csv|
# # Raises NoMethodError (undefined method `collect' for :foo:Symbol)
# csv << :foo
# end
#
# Raises an exception if the output stream is not opened for writing:
# path = 't.csv'
# File.write(path, '')
# File.open(path) do |file|
# CSV.open(file) do |csv|
# # Raises IOError (not opened for writing)
# csv << ['foo', 0]
# end
# end
def <<(row)
writer << row
self
end
alias_method :add_row, :<<
alias_method :puts, :<<
# :call-seq:
# convert(converter_name) -> array_of_procs
# convert {|field, field_info| ... } -> array_of_procs
#
# - With no block, installs a field converter (a \Proc).
# - With a block, defines and installs a custom field converter.
# - Returns the \Array of installed field converters.
#
# - Argument +converter_name+, if given, should be the name
# of an existing field converter.
#
# See {Field Converters}[#class-CSV-label-Field+Converters].
# ---
#
# With no block, installs a field converter:
# csv = CSV.new('')
# csv.convert(:integer)
# csv.convert(:float)
# csv.convert(:date)
# csv.converters # => [:integer, :float, :date]
#
# ---
#
# The block, if given, is called for each field:
# - Argument +field+ is the field value.
# - Argument +field_info+ is a CSV::FieldInfo object
# containing details about the field.
#
# The examples here assume the prior execution of:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# Example giving a block:
# csv = CSV.open(path)
# csv.convert {|field, field_info| p [field, field_info]; field.upcase }
# csv.read # => [["FOO", "0"], ["BAR", "1"], ["BAZ", "2"]]
#
# Output:
# ["foo", #<struct CSV::FieldInfo index=0, line=1, header=nil>]
# ["0", #<struct CSV::FieldInfo index=1, line=1, header=nil>]
# ["bar", #<struct CSV::FieldInfo index=0, line=2, header=nil>]
# ["1", #<struct CSV::FieldInfo index=1, line=2, header=nil>]
# ["baz", #<struct CSV::FieldInfo index=0, line=3, header=nil>]
# ["2", #<struct CSV::FieldInfo index=1, line=3, header=nil>]
#
# The block need not return a \String object:
# csv = CSV.open(path)
# csv.convert {|field, field_info| field.to_sym }
# csv.read # => [[:foo, :"0"], [:bar, :"1"], [:baz, :"2"]]
#
# If +converter_name+ is given, the block is not called:
# csv = CSV.open(path)
# csv.convert(:integer) {|field, field_info| fail 'Cannot happen' }
# csv.read # => [["foo", 0], ["bar", 1], ["baz", 2]]
#
# ---
#
# Raises a parse-time exception if +converter_name+ is not the name of a built-in
# field converter:
# csv = CSV.open(path)
# csv.convert(:nosuch) => [nil]
# # Raises NoMethodError (undefined method `arity' for nil:NilClass)
# csv.read
def convert(name = nil, &converter)
parser_fields_converter.add_converter(name, &converter)
end
# :call-seq:
# header_convert(converter_name) -> array_of_procs
# header_convert {|header, field_info| ... } -> array_of_procs
#
# - With no block, installs a header converter (a \Proc).
# - With a block, defines and installs a custom header converter.
# - Returns the \Array of installed header converters.
#
# - Argument +converter_name+, if given, should be the name
# of an existing header converter.
#
# See {Header Converters}[#class-CSV-label-Header+Converters].
# ---
#
# With no block, installs a header converter:
# csv = CSV.new('')
# csv.header_convert(:symbol)
# csv.header_convert(:downcase)
# csv.header_converters # => [:symbol, :downcase]
#
# ---
#
# The block, if given, is called for each header:
# - Argument +header+ is the header value.
# - Argument +field_info+ is a CSV::FieldInfo object
# containing details about the header.
#
# The examples here assume the prior execution of:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
#
# Example giving a block:
# csv = CSV.open(path, headers: true)
# csv.header_convert {|header, field_info| p [header, field_info]; header.upcase }
# table = csv.read
# table # => #<CSV::Table mode:col_or_row row_count:4>
# table.headers # => ["NAME", "VALUE"]
#
# Output:
# ["Name", #<struct CSV::FieldInfo index=0, line=1, header=nil>]
# ["Value", #<struct CSV::FieldInfo index=1, line=1, header=nil>]
# The block need not return a \String object:
# csv = CSV.open(path, headers: true)
# csv.header_convert {|header, field_info| header.to_sym }
# table = csv.read
# table.headers # => [:Name, :Value]
#
# If +converter_name+ is given, the block is not called:
# csv = CSV.open(path, headers: true)
# csv.header_convert(:downcase) {|header, field_info| fail 'Cannot happen' }
# table = csv.read
# table.headers # => ["name", "value"]
# ---
#
# Raises a parse-time exception if +converter_name+ is not the name of a built-in
# field converter:
# csv = CSV.open(path, headers: true)
# csv.header_convert(:nosuch)
# # Raises NoMethodError (undefined method `arity' for nil:NilClass)
# csv.read
def header_convert(name = nil, &converter)
header_fields_converter.add_converter(name, &converter)
end
include Enumerable
# :call-seq:
# csv.each -> enumerator
# csv.each {|row| ...}
#
# Calls the block with each successive row.
# The data source must be opened for reading.
#
# Without headers:
# string = "foo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string)
# csv.each do |row|
# p row
# end
# Output:
# ["foo", "0"]
# ["bar", "1"]
# ["baz", "2"]
#
# With headers:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string, headers: true)
# csv.each do |row|
# p row
# end
# Output:
# <CSV::Row "Name":"foo" "Value":"0">
# <CSV::Row "Name":"bar" "Value":"1">
# <CSV::Row "Name":"baz" "Value":"2">
#
# ---
#
# Raises an exception if the source is not opened for reading:
# string = "foo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string)
# csv.close
# # Raises IOError (not opened for reading)
# csv.each do |row|
# p row
# end
def each(&block)
parser_enumerator.each(&block)
end
# :call-seq:
# csv.read -> array or csv_table
#
# Forms the remaining rows from +self+ into:
# - A CSV::Table object, if headers are in use.
# - An \Array of Arrays, otherwise.
#
# The data source must be opened for reading.
#
# Without headers:
# string = "foo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
# csv = CSV.open(path)
# csv.read # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# With headers:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# path = 't.csv'
# File.write(path, string)
# csv = CSV.open(path, headers: true)
# csv.read # => #<CSV::Table mode:col_or_row row_count:4>
#
# ---
#
# Raises an exception if the source is not opened for reading:
# string = "foo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string)
# csv.close
# # Raises IOError (not opened for reading)
# csv.read
def read
rows = to_a
if parser.use_headers?
Table.new(rows, headers: parser.headers)
else
rows
end
end
alias_method :readlines, :read
# :call-seq:
# csv.header_row? -> true or false
#
# Returns +true+ if the next row to be read is a header row\;
# +false+ otherwise.
#
# Without headers:
# string = "foo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string)
# csv.header_row? # => false
#
# With headers:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string, headers: true)
# csv.header_row? # => true
# csv.shift # => #<CSV::Row "Name":"foo" "Value":"0">
# csv.header_row? # => false
#
# ---
#
# Raises an exception if the source is not opened for reading:
# string = "foo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string)
# csv.close
# # Raises IOError (not opened for reading)
# csv.header_row?
def header_row?
parser.header_row?
end
# :call-seq:
# csv.shift -> array, csv_row, or nil
#
# Returns the next row of data as:
# - An \Array if no headers are used.
# - A CSV::Row object if headers are used.
#
# The data source must be opened for reading.
#
# Without headers:
# string = "foo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string)
# csv.shift # => ["foo", "0"]
# csv.shift # => ["bar", "1"]
# csv.shift # => ["baz", "2"]
# csv.shift # => nil
#
# With headers:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string, headers: true)
# csv.shift # => #<CSV::Row "Name":"foo" "Value":"0">
# csv.shift # => #<CSV::Row "Name":"bar" "Value":"1">
# csv.shift # => #<CSV::Row "Name":"baz" "Value":"2">
# csv.shift # => nil
#
# ---
#
# Raises an exception if the source is not opened for reading:
# string = "foo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string)
# csv.close
# # Raises IOError (not opened for reading)
# csv.shift
def shift
if @eof_error
eof_error, @eof_error = @eof_error, nil
raise eof_error
end
begin
parser_enumerator.next
rescue StopIteration
nil
end
end
alias_method :gets, :shift
alias_method :readline, :shift
# :call-seq:
# csv.inspect -> string
#
# Returns a \String showing certain properties of +self+:
# string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# csv = CSV.new(string, headers: true)
# s = csv.inspect
# s # => "#<CSV io_type:StringIO encoding:UTF-8 lineno:0 col_sep:\",\" row_sep:\"\\n\" quote_char:\"\\\"\" headers:true>"
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
["lineno", "col_sep", "row_sep", "quote_char"].each do |attr_name|
if a = __send__(attr_name)
str << " " << attr_name << ":" << a.inspect
end
end
["skip_blanks", "liberal_parsing"].each do |attr_name|
if a = __send__("#{attr_name}?")
str << " " << attr_name << ":" << a.inspect
end
end
_headers = headers
str << " headers:" << _headers.inspect if _headers
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
private
def determine_encoding(encoding, internal_encoding)
# honor the IO encoding if we can, otherwise default to ASCII-8BIT
io_encoding = raw_encoding
return io_encoding if io_encoding
return Encoding.find(internal_encoding) if internal_encoding
if encoding
encoding, = encoding.split(":", 2) if encoding.is_a?(String)
return Encoding.find(encoding)
end
Encoding.default_internal || Encoding.default_external
end
def normalize_converters(converters)
converters ||= []
unless converters.is_a?(Array)
converters = [converters]
end
converters.collect do |converter|
case converter
when Proc # custom code block
[nil, converter]
else # by name
[converter, nil]
end
end
end
#
# Processes +fields+ with <tt>@converters</tt>, or <tt>@header_converters</tt>
# if +headers+ is passed as +true+, returning the converted field set. Any
# converter that changes the field into something other than a String halts
# the pipeline of conversion for that field. This is primarily an efficiency
# shortcut.
#
def convert_fields(fields, headers = false)
if headers
header_fields_converter.convert(fields, nil, 0)
else
parser_fields_converter.convert(fields, @headers, lineno)
end
end
#
# Returns the encoding of the internal IO object.
#
def raw_encoding
if @io.respond_to? :internal_encoding
@io.internal_encoding || @io.external_encoding
elsif @io.respond_to? :encoding
@io.encoding
else
nil
end
end
def parser_fields_converter
@parser_fields_converter ||= build_parser_fields_converter
end
def build_parser_fields_converter
specific_options = {
builtin_converters_name: :Converters,
}
options = @base_fields_converter_options.merge(specific_options)
build_fields_converter(@initial_converters, options)
end
def header_fields_converter
@header_fields_converter ||= build_header_fields_converter
end
def build_header_fields_converter
specific_options = {
builtin_converters_name: :HeaderConverters,
accept_nil: true,
}
options = @base_fields_converter_options.merge(specific_options)
build_fields_converter(@initial_header_converters, options)
end
def writer_fields_converter
@writer_fields_converter ||= build_writer_fields_converter
end
def build_writer_fields_converter
build_fields_converter(@initial_write_converters,
@write_fields_converter_options)
end
def build_fields_converter(initial_converters, options)
fields_converter = FieldsConverter.new(options)
normalize_converters(initial_converters).each do |name, converter|
fields_converter.add_converter(name, &converter)
end
fields_converter
end
def parser
@parser ||= Parser.new(@io, parser_options)
end
def parser_options
@parser_options.merge(header_fields_converter: header_fields_converter,
fields_converter: parser_fields_converter)
end
def parser_enumerator
@parser_enumerator ||= parser.parse
end
def writer
@writer ||= Writer.new(@io, writer_options)
end
def writer_options
@writer_options.merge(header_fields_converter: header_fields_converter,
fields_converter: writer_fields_converter)
end
end
# Passes +args+ to CSV::instance.
#
# CSV("CSV,data").read
# #=> [["CSV", "data"]]
#
# If a block is given, the instance is passed the block and the return value
# becomes the return value of the block.
#
# CSV("CSV,data") { |c|
# c.read.any? { |a| a.include?("data") }
# } #=> true
#
# CSV("CSV,data") { |c|
# c.read.any? { |a| a.include?("zombies") }
# } #=> false
#
# CSV options may also be given.
#
# io = StringIO.new
# CSV(io, col_sep: ";") { |csv| csv << ["a", "b", "c"] }
#
# This API is not Ractor-safe.
#
def CSV(*args, **options, &block)
CSV.instance(*args, **options, &block)
end
require_relative "csv/version"
require_relative "csv/core_ext/array"
require_relative "csv/core_ext/string"
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