CSV

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 "\n".

• A column separator delimits fields in a row. A common column separator is the comma character ",".

This CSV String, with row separator "\n" and column separator ",", 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)”, especially its section “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.

Parsing a String¶ ↑

The input to be parsed can be a string:

string = "foo,0\nbar,1\nbaz,2\n" 

Method ::parse returns the entire CSV data:

CSV.parse(string) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Method ::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 ::read returns the entire CSV data:

CSV.read(path) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Method ::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 ::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 ::read returns the entire CSV data:

File.open(path) do |file| CSV.read(file) end # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

As does method ::parse:

File.open(path) do |file| CSV.parse(file) end # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Method ::parse_line returns only the first row:

File.open(path) do |file| CSV.parse_line(file) end # => ["foo", "0"] 

Method ::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 ::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 ::generate returns a String; this example uses method #<< 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 ::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 Array#to_csv, which forms an Array into a String:

['foo', '0'].to_csv # => "foo,0\n" 

“Filtering” CSV¶ ↑

Method ::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 ::new returns a new CSV object.

• Method ::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: "", # For generating. write_headers: nil, quote_empty: true, force_quotes: false, write_converters: nil, write_nil_value: nil, write_empty_value: "", strip: false, } 

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..

• 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.

Option row_sep¶ ↑

Specifies the row separator, a String or the Symbol :auto (see below), to be used for both parsing and generating.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:row_sep) # => :auto 

---

When row_sep is a String, that String becomes the row separator. The String will be transcoded into the data’s Encoding before use.

Using "\n":

row_sep = "\n" str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using | (pipe):

row_sep = '|' str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0|bar,1|baz,2|" ary = CSV.parse(str, row_sep: row_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using -- (two hyphens):

row_sep = '--' str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0--bar,1--baz,2--" ary = CSV.parse(str, row_sep: row_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using '' (empty string):

row_sep = '' str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0bar,1baz,2" ary = CSV.parse(str, row_sep: row_sep) ary # => [["foo", "0bar", "1baz", "2"]] 

---

When row_sep is the Symbol :auto (the default), generating uses "\n" as the row separator:

str = CSV.generate do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" 

Parsing, on the other hand, invokes auto-discovery of the row separator.

Auto-discovery reads ahead in the data looking for the next \r\n, \n, or \r sequence. The sequence will be selected even if it occurs in a quoted field, assuming that you would have the same line endings there.

Example:

str = CSV.generate do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

The default $INPUT_RECORD_SEPARATOR ($/) is used if any of the following is true:

• None of those sequences is found.

• Data is ARGF, STDIN, STDOUT, or STDERR.

• The stream is only available for output.

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.

---

Raises an exception if the given value is not String-convertible:

row_sep = BasicObject.new # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.generate(ary, row_sep: row_sep) # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.parse(str, row_sep: row_sep) 

Option col_sep¶ ↑

Specifies the String field separator to be used for both parsing and generating. The String will be transcoded into the data’s Encoding before use.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:col_sep) # => "," (comma) 

Using the default (comma):

str = CSV.generate do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using : (colon):

col_sep = ':' str = CSV.generate(col_sep: col_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo:0\nbar:1\nbaz:2\n" ary = CSV.parse(str, col_sep: col_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using :: (two colons):

col_sep = '::' str = CSV.generate(col_sep: col_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo::0\nbar::1\nbaz::2\n" ary = CSV.parse(str, col_sep: col_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using '' (empty string):

col_sep = '' str = CSV.generate(col_sep: col_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo0\nbar1\nbaz2\n" 

---

Raises an exception if parsing with the empty String:

col_sep = '' # Raises ArgumentError (:col_sep must be 1 or more characters: "") CSV.parse("foo0\nbar1\nbaz2\n", col_sep: col_sep) 

Raises an exception if the given value is not String-convertible:

col_sep = BasicObject.new # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.generate(line, col_sep: col_sep) # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.parse(str, col_sep: col_sep) 

Option quote_char¶ ↑

Specifies the character (String of length 1) used used to quote fields in both parsing and generating. This String will be transcoded into the data’s Encoding before use.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:quote_char) # => "\"" (double quote) 

This is useful for an application that incorrectly uses ' (single-quote) to quote fields, instead of the correct " (double-quote).

Using the default (double quote):

str = CSV.generate do |csv| csv << ['foo', 0] csv << ["'bar'", 1] csv << ['"baz"', 2] end str # => "foo,0\n'bar',1\n\"\"\"baz\"\"\",2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["'bar'", "1"], ["\"baz\"", "2"]] 

Using ' (single-quote):

quote_char = "'" str = CSV.generate(quote_char: quote_char) do |csv| csv << ['foo', 0] csv << ["'bar'", 1] csv << ['"baz"', 2] end str # => "foo,0\n'''bar''',1\n\"baz\",2\n" ary = CSV.parse(str, quote_char: quote_char) ary # => [["foo", "0"], ["'bar'", "1"], ["\"baz\"", "2"]] 

---

Raises an exception if the String length is greater than 1:

# Raises ArgumentError (:quote_char has to be nil or a single character String) CSV.new('', quote_char: 'xx') 

Raises an exception if the value is not a String:

# Raises ArgumentError (:quote_char has to be nil or a single character String) CSV.new('', quote_char: :foo) 

Option field_size_limit¶ ↑

Specifies the Integer field size limit.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:field_size_limit) # => nil 

This is a maximum size CSV will read ahead looking for the closing quote for a field. (In truth, it reads to the first line ending beyond this size.) If a quote cannot be found within the limit CSV will raise a MalformedCSVError, assuming the data is faulty. You can use this limit to prevent what are effectively DoS attacks on the parser. However, this limit can cause a legitimate parse to fail; therefore the default value is nil (no limit).

For the examples in this section:

str = <<~EOT "a","b" " 2345 ","" EOT str # => "\"a\",\"b\"\n\"\n2345\n\",\"\"\n"

Using the default nil:

ary = CSV.parse(str) ary # => [["a", "b"], ["\n2345\n", ""]] 

Using 50:

field_size_limit = 50 ary = CSV.parse(str, field_size_limit: field_size_limit) ary # => [["a", "b"], ["\n2345\n", ""]] 

---

Raises an exception if a field is too long:

big_str = "123456789\n" * 1024 # Raises CSV::MalformedCSVError (Field size exceeded in line 1.) CSV.parse('valid,fields,"' + big_str + '"', field_size_limit: 2048) 

Option converters¶ ↑

Specifies converters to be used in parsing fields. See Field Converters

Default value:

CSV::DEFAULT_OPTIONS.fetch(:converters) # => nil 

The value may be a field converter name (see Stored Converters):

str = '1,2,3' # Without a converter array = CSV.parse_line(str) array # => ["1", "2", "3"] # With built-in converter :integer array = CSV.parse_line(str, converters: :integer) array # => [1, 2, 3] 

The value may be a converter list (see Converter Lists):

str = '1,3.14159' # Without converters array = CSV.parse_line(str) array # => ["1", "3.14159"] # With built-in converters array = CSV.parse_line(str, converters: [:integer, :float]) array # => [1, 3.14159] 

The value may be a Proc custom converter: (see Custom Field Converters):

str = ' foo , bar , baz ' # Without a converter array = CSV.parse_line(str) array # => [" foo ", " bar ", " baz "] # With a custom converter array = CSV.parse_line(str, converters: proc {|field| field.strip }) array # => ["foo", "bar", "baz"] 

See also Custom Field Converters

---

Raises an exception if the converter is not a converter name or a Proc:

str = 'foo,0' # Raises NoMethodError (undefined method `arity' for nil:NilClass) CSV.parse(str, converters: :foo) 

Option unconverted_fields¶ ↑

Specifies the boolean that determines whether unconverted field values are to be available.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:unconverted_fields) # => nil 

The unconverted field values are those found in the source data, prior to any conversions performed via option converters.

When option unconverted_fields is true, each returned row (Array or CSV::Row) has an added method, unconverted_fields, that returns the unconverted field values:

str = <<-EOT foo,0 bar,1 baz,2 EOT # Without unconverted_fields csv = CSV.parse(str, converters: :integer) csv # => [["foo", 0], ["bar", 1], ["baz", 2]] csv.first.respond_to?(:unconverted_fields) # => false # With unconverted_fields csv = CSV.parse(str, converters: :integer, unconverted_fields: true) csv # => [["foo", 0], ["bar", 1], ["baz", 2]] csv.first.respond_to?(:unconverted_fields) # => true csv.first.unconverted_fields # => ["foo", "0"] 

Option headers¶ ↑

Specifies a boolean, Symbol, Array, or String to be used to define column headers.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:headers) # => false 

---

Without headers:

str = <<-EOT Name,Count foo,0 bar,1 bax,2 EOT csv = CSV.new(str) csv # => #<CSV io_type:StringIO encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\""> csv.headers # => nil csv.shift # => ["Name", "Count"] 

---

If set to true or the Symbol :first_row, the first row of the data is treated as a row of headers:

str = <<-EOT Name,Count foo,0 bar,1 bax,2 EOT csv = CSV.new(str, headers: true) csv # => #<CSV io_type:StringIO encoding:UTF-8 lineno:2 col_sep:"," row_sep:"\n" quote_char:"\"" headers:["Name", "Count"]> csv.headers # => ["Name", "Count"] csv.shift # => #<CSV::Row "Name":"bar" "Count":"1"> 

---

If set to an Array, the Array elements are treated as headers:

str = <<-EOT foo,0 bar,1 bax,2 EOT csv = CSV.new(str, headers: ['Name', 'Count']) csv csv.headers # => ["Name", "Count"] csv.shift # => #<CSV::Row "Name":"bar" "Count":"1"> 

---

If set to a String str, method CSV::parse_line(str, options) is called with the current options, and the returned Array is treated as headers:

str = <<-EOT foo,0 bar,1 bax,2 EOT csv = CSV.new(str, headers: 'Name,Count') csv csv.headers # => ["Name", "Count"] csv.shift # => #<CSV::Row "Name":"bar" "Count":"1"> 

Option return_headers¶ ↑

Specifies the boolean that determines whether method shift returns or ignores the header row.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:return_headers) # => false 

Examples:

str = <<-EOT Name,Count foo,0 bar,1 bax,2 EOT # Without return_headers first row is str. csv = CSV.new(str, headers: true) csv.shift # => #<CSV::Row "Name":"foo" "Count":"0"> # With return_headers first row is headers. csv = CSV.new(str, headers: true, return_headers: true) csv.shift # => #<CSV::Row "Name":"Name" "Count":"Count"> 

Option header_converters¶ ↑

Specifies converters to be used in parsing headers. See Header Converters

Default value:

CSV::DEFAULT_OPTIONS.fetch(:header_converters) # => nil 

Identical in functionality to option converters except that:

• The converters apply only to the header row.

• The built-in header converters are :downcase and :symbol.

This section assumes prior execution of:

str = <<-EOT Name,Value foo,0 bar,1 baz,2 EOT # With no header converter table = CSV.parse(str, headers: true) table.headers # => ["Name", "Value"] 

The value may be a header converter name (see Stored Converters):

table = CSV.parse(str, headers: true, header_converters: :downcase) table.headers # => ["name", "value"] 

The value may be a converter list (see Converter Lists):

header_converters = [:downcase, :symbol] table = CSV.parse(str, headers: true, header_converters: header_converters) table.headers # => [:name, :value] 

The value may be a Proc custom converter (see Custom Header Converters):

upcase_converter = proc {|field| field.upcase } table = CSV.parse(str, headers: true, header_converters: upcase_converter) table.headers # => ["NAME", "VALUE"] 

See also Custom Header Converters

Option skip_blanks¶ ↑

Specifies a boolean that determines whether blank lines in the input will be ignored; a line that contains a column separator is not considered to be blank.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:skip_blanks) # => false 

See also option skiplines.

For examples in this section:

str = <<-EOT foo,0 bar,1 baz,2 , EOT 

Using the default, false:

ary = CSV.parse(str) ary # => [["foo", "0"], [], ["bar", "1"], ["baz", "2"], [], [nil, nil]] 

Using true:

ary = CSV.parse(str, skip_blanks: true) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"], [nil, nil]] 

Using a truthy value:

ary = CSV.parse(str, skip_blanks: :foo) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"], [nil, nil]] 

Option skip_lines¶ ↑

Specifies an object to use in identifying comment lines in the input that are to be ignored:

• If a Regexp, ignores lines that match it.

• If a String, converts it to a Regexp, ignores lines that match it.

• If nil, no lines are considered to be comments.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:skip_lines) # => nil 

For examples in this section:

str = <<-EOT # Comment foo,0 bar,1 baz,2 # Another comment EOT str # => "# Comment\nfoo,0\nbar,1\nbaz,2\n# Another comment\n" 

Using the default, nil:

ary = CSV.parse(str) ary # => [["# Comment"], ["foo", "0"], ["bar", "1"], ["baz", "2"], ["# Another comment"]] 

Using a Regexp:

ary = CSV.parse(str, skip_lines: /^#/) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using a String:

ary = CSV.parse(str, skip_lines: '#') ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

---

Raises an exception if given an object that is not a Regexp, a String, or nil:

# Raises ArgumentError (:skip_lines has to respond to #match: 0) CSV.parse(str, skip_lines: 0) 

Option strip¶ ↑

Specifies the boolean value that determines whether whitespace is stripped from each input field.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:strip) # => false 

With default value false:

ary = CSV.parse_line(' a , b ') ary # => [" a ", " b "] 

With value true:

ary = CSV.parse_line(' a , b ', strip: true) ary # => ["a", "b"] 

Option liberal_parsing¶ ↑

Specifies the boolean value that determines whether CSV will attempt to parse input not conformant with RFC 4180, such as double quotes in unquoted fields.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:liberal_parsing) # => false 

For examples in this section:

str = 'is,this "three, or four",fields' 

Without liberal_parsing:

# Raises CSV::MalformedCSVError (Illegal quoting in str 1.) CSV.parse_line(str) 

With liberal_parsing:

ary = CSV.parse_line(str, liberal_parsing: true) ary # => ["is", "this \"three", " or four\"", "fields"] 

Option nil_value¶ ↑

Specifies the object that is to be substituted for each null (no-text) field.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:nil_value) # => nil 

With the default, nil:

CSV.parse_line('a,,b,,c') # => ["a", nil, "b", nil, "c"] 

With a different object:

CSV.parse_line('a,,b,,c', nil_value: 0) # => ["a", 0, "b", 0, "c"] 

Option empty_value¶ ↑

Specifies the object that is to be substituted for each field that has an empty String.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:empty_value) # => "" (empty string) 

With the default, "":

CSV.parse_line('a,"",b,"",c') # => ["a", "", "b", "", "c"] 

With a different object:

CSV.parse_line('a,"",b,"",c', empty_value: 'x') # => ["a", "x", "b", "x", "c"] 

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.

Option row_sep¶ ↑

Specifies the row separator, a String or the Symbol :auto (see below), to be used for both parsing and generating.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:row_sep) # => :auto 

---

When row_sep is a String, that String becomes the row separator. The String will be transcoded into the data’s Encoding before use.

Using "\n":

row_sep = "\n" str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using | (pipe):

row_sep = '|' str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0|bar,1|baz,2|" ary = CSV.parse(str, row_sep: row_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using -- (two hyphens):

row_sep = '--' str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0--bar,1--baz,2--" ary = CSV.parse(str, row_sep: row_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using '' (empty string):

row_sep = '' str = CSV.generate(row_sep: row_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0bar,1baz,2" ary = CSV.parse(str, row_sep: row_sep) ary # => [["foo", "0bar", "1baz", "2"]] 

---

When row_sep is the Symbol :auto (the default), generating uses "\n" as the row separator:

str = CSV.generate do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" 

Parsing, on the other hand, invokes auto-discovery of the row separator.

Auto-discovery reads ahead in the data looking for the next \r\n, \n, or \r sequence. The sequence will be selected even if it occurs in a quoted field, assuming that you would have the same line endings there.

Example:

str = CSV.generate do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

The default $INPUT_RECORD_SEPARATOR ($/) is used if any of the following is true:

• None of those sequences is found.

• Data is ARGF, STDIN, STDOUT, or STDERR.

• The stream is only available for output.

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.

---

Raises an exception if the given value is not String-convertible:

row_sep = BasicObject.new # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.generate(ary, row_sep: row_sep) # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.parse(str, row_sep: row_sep) 

Option col_sep¶ ↑

Specifies the String field separator to be used for both parsing and generating. The String will be transcoded into the data’s Encoding before use.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:col_sep) # => "," (comma) 

Using the default (comma):

str = CSV.generate do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo,0\nbar,1\nbaz,2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using : (colon):

col_sep = ':' str = CSV.generate(col_sep: col_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo:0\nbar:1\nbaz:2\n" ary = CSV.parse(str, col_sep: col_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using :: (two colons):

col_sep = '::' str = CSV.generate(col_sep: col_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo::0\nbar::1\nbaz::2\n" ary = CSV.parse(str, col_sep: col_sep) ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

Using '' (empty string):

col_sep = '' str = CSV.generate(col_sep: col_sep) do |csv| csv << [:foo, 0] csv << [:bar, 1] csv << [:baz, 2] end str # => "foo0\nbar1\nbaz2\n" 

---

Raises an exception if parsing with the empty String:

col_sep = '' # Raises ArgumentError (:col_sep must be 1 or more characters: "") CSV.parse("foo0\nbar1\nbaz2\n", col_sep: col_sep) 

Raises an exception if the given value is not String-convertible:

col_sep = BasicObject.new # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.generate(line, col_sep: col_sep) # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>) CSV.parse(str, col_sep: col_sep) 

Option quote_char¶ ↑

Specifies the character (String of length 1) used used to quote fields in both parsing and generating. This String will be transcoded into the data’s Encoding before use.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:quote_char) # => "\"" (double quote) 

This is useful for an application that incorrectly uses ' (single-quote) to quote fields, instead of the correct " (double-quote).

Using the default (double quote):

str = CSV.generate do |csv| csv << ['foo', 0] csv << ["'bar'", 1] csv << ['"baz"', 2] end str # => "foo,0\n'bar',1\n\"\"\"baz\"\"\",2\n" ary = CSV.parse(str) ary # => [["foo", "0"], ["'bar'", "1"], ["\"baz\"", "2"]] 

Using ' (single-quote):

quote_char = "'" str = CSV.generate(quote_char: quote_char) do |csv| csv << ['foo', 0] csv << ["'bar'", 1] csv << ['"baz"', 2] end str # => "foo,0\n'''bar''',1\n\"baz\",2\n" ary = CSV.parse(str, quote_char: quote_char) ary # => [["foo", "0"], ["'bar'", "1"], ["\"baz\"", "2"]] 

---

Raises an exception if the String length is greater than 1:

# Raises ArgumentError (:quote_char has to be nil or a single character String) CSV.new('', quote_char: 'xx') 

Raises an exception if the value is not a String:

# Raises ArgumentError (:quote_char has to be nil or a single character String) CSV.new('', quote_char: :foo) 

Option write_headers¶ ↑

Specifies the boolean that determines whether a header row is included in the output; ignored if there are no headers.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:write_headers) # => nil 

Without write_headers:

file_path = 't.csv' CSV.open(file_path,'w', :headers => ['Name','Value'] ) do |csv| csv << ['foo', '0'] end CSV.open(file_path) do |csv| csv.shift end # => ["foo", "0"] 

With write_headers“:

CSV.open(file_path,'w', :write_headers=> true, :headers => ['Name','Value'] ) do |csv| csv << ['foo', '0'] end CSV.open(file_path) do |csv| csv.shift end # => ["Name", "Value"] 

Option force_quotes¶ ↑

Specifies the boolean that determines whether each output field is to be double-quoted.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:force_quotes) # => false 

For examples in this section:

ary = ['foo', 0, nil] 

Using the default, false:

str = CSV.generate_line(ary) str # => "foo,0,\n" 

Using true:

str = CSV.generate_line(ary, force_quotes: true) str # => "\"foo\",\"0\",\"\"\n" 

Option quote_empty¶ ↑

Specifies the boolean that determines whether an empty value is to be double-quoted.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:quote_empty) # => true 

With the default true:

CSV.generate_line(['"', ""]) # => "\"\"\"\",\"\"\n" 

With false:

CSV.generate_line(['"', ""], quote_empty: false) # => "\"\"\"\",\n" 

Option write_converters¶ ↑

Specifies converters to be used in generating fields. See Write Converters

Default value:

CSV::DEFAULT_OPTIONS.fetch(:write_converters) # => nil 

With no write converter:

str = CSV.generate_line(["\na\n", "\tb\t", " c "]) str # => "\"\na\n\",\tb\t, c \n" 

With a write converter:

strip_converter = proc {|field| field.strip } str = CSV.generate_line(["\na\n", "\tb\t", " c "], write_converters: strip_converter) str # => "a,b,c\n" 

With two write converters (called in order):

upcase_converter = proc {|field| field.upcase } downcase_converter = proc {|field| field.downcase } write_converters = [upcase_converter, downcase_converter] str = CSV.generate_line(['a', 'b', 'c'], write_converters: write_converters) str # => "a,b,c\n" 

See also Write Converters

---

Raises an exception if the converter returns a value that is neither nil nor String-convertible:

bad_converter = proc {|field| BasicObject.new } # Raises NoMethodError (undefined method `is_a?' for #<BasicObject:>) CSV.generate_line(['a', 'b', 'c'], write_converters: bad_converter)# 

Option write_nil_value¶ ↑

Specifies the object that is to be substituted for each nil-valued field.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:write_nil_value) # => nil 

Without the option:

str = CSV.generate_line(['a', nil, 'c', nil]) str # => "a,,c,\n" 

With the option:

str = CSV.generate_line(['a', nil, 'c', nil], write_nil_value: "x") str # => "a,x,c,x\n" 

Option write_empty_value¶ ↑

Specifies the object that is to be substituted for each field that has an empty String.

Default value:

CSV::DEFAULT_OPTIONS.fetch(:write_empty_value) # => "" 

Without the option:

str = CSV.generate_line(['a', '', 'c', '']) str # => "a,\"\",c,\"\"\n" 

With the option:

str = CSV.generate_line(['a', '', 'c', ''], write_empty_value: "x") str # => "a,x,c,x\n" 

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.

• See 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.

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 field.strip:

strip_converter = proc {|field| field.strip } 

In this call to CSV.parse, the keyword argument converters: string_converter 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::Info 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:

• :integer: converts each String-embedded integer into a true Integer.

• :float: converts each String-embedded float into a true Float.

• :date: converts each String-embedded date into a true Date.

• :date_time: 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, :strip:

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:

• :downcase: Downcases each header.

• :symbol: Converts each header to a Symbol.

There is no such storage structure for write headers.

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 with a parsing method:

  ary = CSV.parse(string, converters: :integer) ary # => [0, 1, 2] # => [["foo", 0], ["bar", 1], ["baz", 2]] 

• Using 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, :col_sep, :row_sep, and :quote_char must be transcoded to match your data. Hopefully this makes the entire process feel transparent, since CSV’s defaults should just magically work for your data. However, you can set these values manually in the target Encoding to avoid the translation.

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

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

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

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

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

frozen_string_literal: true

frozen_string_literal: true

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" 

 # File csv.rb, line 1051 def filter(input=nil, output=nil, **options) # parse options for input, output, or both in_options, out_options = Hash.new, {row_sep: $INPUT_RECORD_SEPARATOR} 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 

string = "foo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

CSV.foreach(path) {|row| p row } 

["foo", "0"] ["bar", "1"] ["baz", "2"] 

File.open(path) do |file| CSV.foreach(file) {|row| p row } end 

["foo", "0"] ["bar", "1"] ["baz", "2"] 

CSV.foreach(path) # => #<Enumerator: CSV:foreach("t.csv", "r")> CSV.foreach(File.open(path)) # => #<Enumerator: CSV:foreach(#<File:t.csv>, "r")> 

CSV.foreach(File.open(path), encoding: 'foo:bar') {|row| } 

warning: Unsupported encoding foo ignored warning: Unsupported encoding bar ignored

string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

CSV.foreach(path, headers: true) {|row| p row } 

#<CSV::Row "Name":"foo" "Count":"0"> #<CSV::Row "Name":"bar" "Count":"1"> #<CSV::Row "Name":"baz" "Count":"2"> 

File.open(path) do |file| CSV.foreach(file, headers: true) {|row| p row } end 

#<CSV::Row "Name":"foo" "Count":"0"> #<CSV::Row "Name":"bar" "Count":"1"> #<CSV::Row "Name":"baz" "Count":"2"> 

# Raises Errno::ENOENT (No such file or directory @ rb_sysopen - nosuch.csv): CSV.foreach('nosuch.csv') {|row| } 

io = File.open(path, 'w') {|row| } # Raises TypeError (no implicit conversion of nil into String): CSV.foreach(io) {|row| } 

# Raises ArgumentError (invalid access mode nosuch): CSV.foreach(path, 'nosuch') {|row| } 

 # File csv.rb, line 1202 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 

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 

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 

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 TypeError (no implicit conversion of Integer into String) CSV.generate(0) 

 # File csv.rb, line 1268 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 

CSV.generate_line(['foo', '0']) # => "foo,0\n" 

# Raises NoMethodError (undefined method `find' for :foo:Symbol) CSV.generate_line(:foo) 

 # File csv.rb, line 1316 def generate_line(row, **options) options = {row_sep: $INPUT_RECORD_SEPARATOR}.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 

s0 = 's0' csv0 = CSV.instance(s0) csv0.class # => CSV 

csv1 = CSV.instance(s0) csv1.class # => CSV csv1.equal?(csv0) # => true # Same CSV object 

s1 = 's1' csv2 = CSV.instance(s1) csv2.equal?(csv0) # => false # Different CSV object 

csv3 = CSV.instance(s0) csv3.equal?(csv0) # true # Same CSV object csv4 = CSV.instance(s1) csv4.equal?(csv2) # true # Same CSV object 

CSV.instance(s0) {|csv| :foo } # => :foo 

 # File csv.rb, line 980 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 

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

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

 # File csv.rb, line 1731 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: "", quote_empty: true, write_converters: nil, write_nil_value: nil, write_empty_value: "", strip: false) 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 

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)

string = "foo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

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:"\""> 

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:"\""> 

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:"\""> 

#<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\""> 

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:"\""> 

#<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\""> 

# Raises TypeError (no implicit conversion of Symbol into String) CSV.open(:foo) 

 # File csv.rb, line 1411 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 

string = "foo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

a_of_a = CSV.parse(string) a_of_a # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

a_of_a = File.open(path) do |file| CSV.parse(file) end a_of_a # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

CSV.parse(string) {|row| p row } 

["foo", "0"] ["bar", "1"] ["baz", "2"] 

File.open(path) do |file| CSV.parse(file) {|row| p row } end 

["foo", "0"] ["bar", "1"] ["baz", "2"] 

string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

csv_table = CSV.parse(string, headers: ['Name', 'Count']) csv_table # => #<CSV::Table mode:col_or_row row_count:5> 

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> 

CSV.parse(string, headers: ['Name', 'Count']) {|row| p row } 

# <CSV::Row "Name":"foo" "Count":"0"> # <CSV::Row "Name":"bar" "Count":"1"> # <CSV::Row "Name":"baz" "Count":"2"> 

File.open(path) do |file| CSV.parse(file, headers: ['Name', 'Count']) {|row| p row } end 

# <CSV::Row "Name":"foo" "Count":"0"> # <CSV::Row "Name":"bar" "Count":"1"> # <CSV::Row "Name":"baz" "Count":"2"> 

# Raises NoMethodError (undefined method `close' for :foo:Symbol) CSV.parse(:foo) 

 # File csv.rb, line 1558 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 

string = "foo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

CSV.parse_line(string) # => ["foo", "0"] 

File.open(path) do |file| CSV.parse_line(file) # => ["foo", "0"] end # => ["foo", "0"] 

CSV.parse_line('') # => nil 

string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

CSV.parse_line(string, headers: true) # => #<CSV::Row "Name":"foo" "Count":"0"> 

File.open(path) do |file| CSV.parse_line(file, headers: true) end # => #<CSV::Row "Name":"foo" "Count":"0"> 

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

 # File csv.rb, line 1631 def parse_line(line, **options) new(line, **options).each.first end 

string = "foo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) CSV.read(path) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]] 

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> 

 # File csv.rb, line 1655 def read(path, **options) open(path, **options) { |csv| csv.read } end 

 # File csv.rb, line 1663 def readlines(path, **options) read(path, **options) end 

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> 

 # File csv.rb, line 1682 def table(path, **options) default_options = { headers: true, converters: :numeric, header_converters: :symbol, } options = default_options.merge(options) read(path, **options) end 

CSV.generate do |csv| csv << ['foo', 0] csv << ['bar', 1] csv << ['baz', 2] end # => "foo,0\nbar,1\nbaz,2\n" 

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 = ['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" 

CSV.generate do |csv| # Raises NoMethodError (undefined method `collect' for :foo:Symbol) csv << :foo end 

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 

 # File csv.rb, line 2161 def <<(row) writer << row self end 

 # File csv.rb, line 2050 def binmode? if @io.respond_to?(:binmode?) @io.binmode? else false end end 

CSV.new('').col_sep # => "," 

 # File csv.rb, line 1820 def col_sep parser.column_separator end 

csv = CSV.new('') csv.convert(:integer) csv.convert(:float) csv.convert(:date) csv.converters # => [:integer, :float, :date] 

string = "foo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string) 

csv = CSV.open(path) csv.convert {|field, field_info| p [field, field_info]; field.upcase } csv.read # => [["FOO", "0"], ["BAR", "1"], ["BAZ", "2"]] 

["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>]

csv = CSV.open(path) csv.convert {|field, field_info| field.to_sym } csv.read # => [[:foo, :"0"], [:bar, :"1"], [:baz, :"2"]] 

csv = CSV.open(path) csv.convert(:integer) {|field, field_info| fail 'Cannot happen' } csv.read # => [["foo", 0], ["bar", 1], ["baz", 2]] 

csv = CSV.open(path) csv.convert(:nosuch) => [nil] # Raises NoMethodError (undefined method `arity' for nil:NilClass) csv.read

 # File csv.rb, line 2232 def convert(name = nil, &converter) parser_fields_converter.add_converter(name, &converter) end 

csv = CSV.new('') csv.converters # => [] csv.convert(:integer) csv.converters # => [:integer] csv.convert(proc {|x| x.to_s }) csv.converters 

 # File csv.rb, line 1875 def converters parser_fields_converter.map do |converter| name = Converters.rassoc(converter) name ? name.first : converter end end 

string = "foo,0\nbar,1\nbaz,2\n" csv = CSV.new(string) csv.each do |row| p row end 

["foo", "0"] ["bar", "1"] ["baz", "2"] 

string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n" csv = CSV.new(string, headers: true) csv.each do |row| p row end 

<CSV::Row "Name":"foo" "Value":"0"> <CSV::Row "Name":"bar" "Value":"1"> <CSV::Row "Name":"baz" "Value":"2">

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 

 # File csv.rb, line 2343 def each(&block) parser_enumerator.each(&block) end 

 # File csv.rb, line 2086 def eof? return false if @eof_error begin parser_enumerator.peek false rescue MalformedCSVError => error @eof_error = error false rescue StopIteration true end end 

CSV.new('').field_size_limit # => nil 

 # File csv.rb, line 1850 def field_size_limit parser.field_size_limit end 

 # File csv.rb, line 2058 def flock(*args) raise NotImplementedError unless @io.respond_to?(:flock) @io.flock(*args) end 

CSV.new('').force_quotes? # => false 

 # File csv.rb, line 1961 def force_quotes? @writer_options[:force_quotes] end 

csv = CSV.open(path, headers: true) csv.header_convert {|header, field_info| header.to_sym } table = csv.read table.headers # => [:Name, :Value] 

csv = CSV.open(path, headers: true) csv.header_convert(:downcase) {|header, field_info| fail 'Cannot happen' } table = csv.read table.headers # => ["name", "value"] 

csv = CSV.open(path, headers: true) csv.header_convert(:nosuch) # Raises NoMethodError (undefined method `arity' for nil:NilClass) csv.read 

 # File csv.rb, line 2298 def header_convert(name = nil, &converter) header_fields_converter.add_converter(name, &converter) end 

CSV.new('').header_converters # => [] 

 # File csv.rb, line 1937 def header_converters header_fields_converter.map do |converter| name = HeaderConverters.rassoc(converter) name ? name.first : converter end end 

string = "foo,0\nbar,1\nbaz,2\n" csv = CSV.new(string) csv.header_row? # => false 

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 

string = "foo,0\nbar,1\nbaz,2\n" csv = CSV.new(string) csv.close # Raises IOError (not opened for reading) csv.header_row? 

 # File csv.rb, line 2414 def header_row? parser.header_row? end 

CSV.new('').headers # => nil 

 # File csv.rb, line 1899 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 

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>" 

 # File csv.rb, line 2473 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 

 # File csv.rb, line 2063 def ioctl(*args) raise NotImplementedError unless @io.respond_to?(:ioctl) @io.ioctl(*args) end 

CSV.new('').liberal_parsing? # => false 

 # File csv.rb, line 1971 def liberal_parsing? parser.liberal_parsing? end 

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 

[1, "foo,0\n"] [2, "bar,1\n"] [3, "baz,2\n"] 

 # File csv.rb, line 2036 def line parser.line end 

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 

[1, ["foo", "0"]] [2, ["bar", "1"]] [3, ["baz", "2"]] 

CSV.generate do |csv| p csv.lineno; csv << ['foo', 0] p csv.lineno; csv << ['bar', 1] p csv.lineno; csv << ['baz', 2] end 

0 1 2 

 # File csv.rb, line 2012 def lineno if @writer @writer.lineno else parser.lineno end end 

 # File csv.rb, line 2068 def path @io.path if @io.respond_to?(:path) end 

CSV.new('').quote_char # => "\"" 

 # File csv.rb, line 1840 def quote_char parser.quote_character end 

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"]] 

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> 

string = "foo,0\nbar,1\nbaz,2\n" csv = CSV.new(string) csv.close # Raises IOError (not opened for reading) csv.read 

 # File csv.rb, line 2378 def read rows = to_a if parser.use_headers? Table.new(rows, headers: parser.headers) else rows end end 

CSV.new('').return_headers? # => false 

 # File csv.rb, line 1917 def return_headers? parser.return_headers? end 

 # File csv.rb, line 2101 def rewind @parser = nil @parser_enumerator = nil @eof_error = nil @writer.rewind if @writer @io.rewind end 

CSV.new('').row_sep # => "\n" 

 # File csv.rb, line 1830 def row_sep parser.row_separator end 

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 

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 

string = "foo,0\nbar,1\nbaz,2\n" csv = CSV.new(string) csv.close # Raises IOError (not opened for reading) csv.shift 

 # File csv.rb, line 2451 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 

CSV.new('').skip_blanks? # => false 

 # File csv.rb, line 1950 def skip_blanks? parser.skip_blanks? end 

CSV.new('').skip_lines # => nil 

 # File csv.rb, line 1860 def skip_lines parser.skip_lines end 

 # File csv.rb, line 2072 def stat(*args) raise NotImplementedError unless @io.respond_to?(:stat) @io.stat(*args) end 

 # File csv.rb, line 2077 def to_i raise NotImplementedError unless @io.respond_to?(:to_i) @io.to_i end 

 # File csv.rb, line 2082 def to_io @io.respond_to?(:to_io) ? @io.to_io : @io end 

CSV.new('').unconverted_fields? # => nil 

 # File csv.rb, line 1889 def unconverted_fields? parser.unconverted_fields? end 

CSV.new('').write_headers? # => nil 

 # File csv.rb, line 1927 def write_headers? @writer_options[:write_headers] end