Yields each environment variable value:
ENV.replace('foo' => '0', 'bar' => '1') # => ENV values = [] ENV.each_value { |value| values.push(value) } # => ENV values # => ["1", "0"]
Returns an Enumerator
if no block given:
e = ENV.each_value # => #<Enumerator: {"bar"=>"1", "foo"=>"0"}:each_value> values = [] e.each { |value| values.push(value) } # => ENV values # => ["1", "0"]
Returns an enumerator which iterates over each line (separated by sep, which defaults to your platform’s newline character) of each file in ARGV
. If a block is supplied, each line in turn will be yielded to the block, otherwise an enumerator is returned. The optional limit argument is an Integer
specifying the maximum length of each line; longer lines will be split according to this limit.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last line of the first file has been returned, the first line of the second file is returned. The ARGF.filename
and ARGF.lineno
methods can be used to determine the filename of the current line and line number of the whole input, respectively.
For example, the following code prints out each line of each named file prefixed with its line number, displaying the filename once per file:
ARGF.each_line do |line| puts ARGF.filename if ARGF.file.lineno == 1 puts "#{ARGF.file.lineno}: #{line}" end
While the following code prints only the first file’s name at first, and the contents with line number counted through all named files.
ARGF.each_line do |line| puts ARGF.filename if ARGF.lineno == 1 puts "#{ARGF.lineno}: #{line}" end
Iterates over each byte of each file in ARGV
. A byte is returned as an Integer
in the range 0..255.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last byte of the first file has been returned, the first byte of the second file is returned. The ARGF.filename
method can be used to determine the filename of the current byte.
If no block is given, an enumerator is returned instead.
For example:
ARGF.bytes.to_a #=> [35, 32, ... 95, 10]
Iterates over each codepoint of each file in ARGF
.
This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last codepoint of the first file has been returned, the first codepoint of the second file is returned. The ARGF.filename
method can be used to determine the name of the file in which the current codepoint appears.
If no block is given, an enumerator is returned instead.
Return the accept character set for all new CGI
instances.
The encoded :quote_char
used in parsing and writing. See CSV::new
for details.
‘each_option’ is an alias of ‘each’.
Returns range or nil
Creates an OptionParser::Switch
from the parameters. The parsed argument value is passed to the given block, where it can be processed.
See at the beginning of OptionParser
for some full examples.
opts
can include the following elements:
One of the following:
:NONE, :REQUIRED, :OPTIONAL
Acceptable option argument format, must be pre-defined with OptionParser.accept
or OptionParser#accept
, or Regexp
. This can appear once or assigned as String
if not present, otherwise causes an ArgumentError
. Examples:
Float, Time, Array
[:text, :binary, :auto] %w[iso-2022-jp shift_jis euc-jp utf8 binary] { "jis" => "iso-2022-jp", "sjis" => "shift_jis" }
Specifies a long style switch which takes a mandatory, optional or no argument. It’s a string of the following form:
"--switch=MANDATORY" or "--switch MANDATORY" "--switch[=OPTIONAL]" "--switch"
Specifies short style switch which takes a mandatory, optional or no argument. It’s a string of the following form:
"-xMANDATORY" "-x[OPTIONAL]" "-x"
There is also a special form which matches character range (not full set of regular expression):
"-[a-z]MANDATORY" "-[a-z][OPTIONAL]" "-[a-z]"
Instead of specifying mandatory or optional arguments directly in the switch parameter, this separate parameter can be used.
"=MANDATORY" "=[OPTIONAL]"
Description string for the option.
"Run verbosely"
If you give multiple description strings, each string will be printed line by line.
Handler for the parsed argument value. Either give a block or pass a Proc
or Method
as an argument.
Returns the portion of the original string before the current match. Equivalent to the special variable $`
.
m = /(.)(.)(\d+)(\d)/.match("THX1138.") m.pre_match #=> "T"
Returns the portion of the original string after the current match. Equivalent to the special variable $'
.
m = /(.)(.)(\d+)(\d)/.match("THX1138: The Movie") m.post_match #=> ": The Movie"
Ensures that names
only includes names for the :rdoc, :clobber_rdoc and :rerdoc. If other names are given an ArgumentError
is raised.
Iterates over all IP addresses for name
.
Iterates over all hostnames for address
.
Iterates over all IP addresses for name
.
Iterates over all hostnames for address
.
Builds a temporary array and traverses that array in reverse order.
If no block is given, an enumerator is returned instead.
(1..3).reverse_each { |v| p v }
produces:
3 2 1
Calls block once for each element in self
, passing that element as a parameter, converting multiple values from yield to an array.
If no block is given, an enumerator is returned instead.
class Foo include Enumerable def each yield 1 yield 1, 2 yield end end Foo.new.each_entry{ |o| p o }
produces:
1 [1, 2] nil
Iterates the given block for each slice of <n> elements. If no block is given, returns an enumerator.
(1..10).each_slice(3) { |a| p a } # outputs below [1, 2, 3] [4, 5, 6] [7, 8, 9] [10]
Iterates the given block for each array of consecutive <n> elements. If no block is given, returns an enumerator.
e.g.:
(1..10).each_cons(3) { |a| p a } # outputs below [1, 2, 3] [2, 3, 4] [3, 4, 5] [4, 5, 6] [5, 6, 7] [6, 7, 8] [7, 8, 9] [8, 9, 10]
Creates an enumerator for each chunked elements. The beginnings of chunks are defined by the block.
This method split each chunk using adjacent elements, elt_before and elt_after, in the receiver enumerator. This method split chunks between elt_before and elt_after where the block returns false
.
The block is called the length of the receiver enumerator minus one.
The result enumerator yields the chunked elements as an array. So each
method can be called as follows:
enum.chunk_while { |elt_before, elt_after| bool }.each { |ary| ... }
Other methods of the Enumerator
class and Enumerable
module, such as to_a
, map
, etc., are also usable.
For example, one-by-one increasing subsequence can be chunked as follows:
a = [1,2,4,9,10,11,12,15,16,19,20,21] b = a.chunk_while {|i, j| i+1 == j } p b.to_a #=> [[1, 2], [4], [9, 10, 11, 12], [15, 16], [19, 20, 21]] c = b.map {|a| a.length < 3 ? a : "#{a.first}-#{a.last}" } p c #=> [[1, 2], [4], "9-12", [15, 16], "19-21"] d = c.join(",") p d #=> "1,2,4,9-12,15,16,19-21"
Increasing (non-decreasing) subsequence can be chunked as follows:
a = [0, 9, 2, 2, 3, 2, 7, 5, 9, 5] p a.chunk_while {|i, j| i <= j }.to_a #=> [[0, 9], [2, 2, 3], [2, 7], [5, 9], [5]]
Adjacent evens and odds can be chunked as follows: (Enumerable#chunk
is another way to do it.)
a = [7, 5, 9, 2, 0, 7, 9, 4, 2, 0] p a.chunk_while {|i, j| i.even? == j.even? }.to_a #=> [[7, 5, 9], [2, 0], [7, 9], [4, 2, 0]]
Enumerable#slice_when
does the same, except splitting when the block returns true
instead of false
.