Search the encoding with specified name. name should be a string.
Encoding.find("US-ASCII") #=> #<Encoding:US-ASCII>
Names which this method accept are encoding names and aliases including following special aliases
default external encoding
default internal encoding
locale encoding
filesystem encoding
An ArgumentError
is raised when no encoding with name. Only Encoding.find("internal")
however returns nil when no encoding named “internal”, in other words, when Ruby
has no default internal encoding.
Rewinds the enumeration sequence to the beginning.
If the enclosed object responds to a “rewind” method, it is called.
Creates a printable version of e.
Returns a Digest
subclass by name
in a thread-safe manner even when on-demand loading is involved.
require 'digest' Digest("MD5") # => Digest::MD5 Digest(:SHA256) # => Digest::SHA256 Digest(:Foo) # => LoadError: library not found for class Digest::Foo -- digest/foo
Returns a string containing a human-readable representation of obj. The default inspect
shows the object’s class name, an encoding of its memory address, and a list of the instance variables and their values (by calling inspect
on each of them). User defined classes should override this method to provide a better representation of obj. When overriding this method, it should return a string whose encoding is compatible with the default external encoding.
[ 1, 2, 3..4, 'five' ].inspect #=> "[1, 2, 3..4, \"five\"]" Time.new.inspect #=> "2008-03-08 19:43:39 +0900" class Foo end Foo.new.inspect #=> "#<Foo:0x0300c868>" class Bar def initialize @bar = 1 end end Bar.new.inspect #=> "#<Bar:0x0300c868 @bar=1>"
Returns a string representation of self
:
x = RuntimeError.new('Boom') x.inspect # => "#<RuntimeError: Boom>" x = RuntimeError.new x.inspect # => "#<RuntimeError: RuntimeError>"
Returns the backtrace (the list of code locations that led to the exception), as an array of strings.
Example (assuming the code is stored in the file named t.rb
):
def division(numerator, denominator) numerator / denominator end begin division(1, 0) rescue => ex p ex.backtrace # ["t.rb:2:in 'Integer#/'", "t.rb:2:in 'Object#division'", "t.rb:6:in '<main>'"] loc = ex.backtrace.first p loc.class # String end
The value returned by this method migth be adjusted when raising (see Kernel#raise
), or during intermediate handling by set_backtrace
.
See also backtrace_locations
that provide the same value, as structured objects. (Note though that two values might not be consistent with each other when backtraces are manually adjusted.)
see Backtraces.
Return the status value associated with this system exit.
Invokes Module.append_features
on each parameter in reverse order.
Returns an array of Refinement
defined within the receiver.
module A refine Integer do end refine String do end end p A.refinements
produces:
[#<refinement:Integer@A>, #<refinement:String@A>]
In the first form, returns an array of the names of all constants accessible from the point of call. This list includes the names of all modules and classes defined in the global scope.
Module.constants.first(4) # => [:ARGF, :ARGV, :ArgumentError, :Array] Module.constants.include?(:SEEK_SET) # => false class IO Module.constants.include?(:SEEK_SET) # => true end
The second form calls the instance method constants
.
Callback invoked whenever the receiver is included in another module or class. This should be used in preference to Module.append_features
if your code wants to perform some action when a module is included in another.
module A def A.included(mod) puts "#{self} included in #{mod}" end end module Enumerable include A end # => prints "A included in Enumerable"
Returns true
if module is included or prepended in mod or one of mod’s ancestors.
module A end class B include A end class C < B end B.include?(A) #=> true C.include?(A) #=> true A.include?(A) #=> false
Returns a list of modules included/prepended in mod (including mod itself).
module Mod include Math include Comparable prepend Enumerable end Mod.ancestors #=> [Enumerable, Mod, Comparable, Math] Math.ancestors #=> [Math] Enumerable.ancestors #=> [Enumerable]
The first form is equivalent to attr_reader
. The second form is equivalent to attr_accessor(name)
but deprecated. The last form is equivalent to attr_reader(name)
but deprecated. Returns an array of defined method names as symbols.
Returns an array of the names of the constants accessible in mod. This includes the names of constants in any included modules (example at start of section), unless the inherit parameter is set to false
.
The implementation makes no guarantees about the order in which the constants are yielded.
IO.constants.include?(:SYNC) #=> true IO.constants(false).include?(:SYNC) #=> false
Also see Module#const_defined?
.
Returns a string representing this module or class. For basic classes and modules, this is the name. For singletons, we show information on the thing we’re attached to as well.
With no arguments, sets the default visibility for subsequently defined methods to private. With arguments, sets the named methods to have private visibility. String
arguments are converted to symbols. An Array
of Symbols and/or Strings is also accepted. If a single argument is passed, it is returned. If no argument is passed, nil is returned. If multiple arguments are passed, the arguments are returned as an array.
module Mod def a() end def b() end private def c() end private :a end Mod.private_instance_methods #=> [:a, :c]
Note that to show a private method on RDoc
, use :doc:
.
Returns a new Date object formed fom the arguments.
With no arguments, returns the date for January 1, -4712:
Date.ordinal.to_s # => "-4712-01-01"
With argument year
, returns the date for January 1 of that year:
Date.ordinal(2001).to_s # => "2001-01-01" Date.ordinal(-2001).to_s # => "-2001-01-01"
With positive argument yday
== n
, returns the date for the nth
day of the given year:
Date.ordinal(2001, 14).to_s # => "2001-01-14"
With negative argument yday
, counts backward from the end of the year:
Date.ordinal(2001, -14).to_s # => "2001-12-18"
Raises an exception if yday
is zero or out of range.
See argument start.
Returns true
if self
is a Friday, false
otherwise.
Returns true
if the date is on or after the date of calendar reform, false
otherwise:
Date.new(1582, 10, 15).gregorian? # => true (Date.new(1582, 10, 15) - 1).gregorian? # => false
Returns the Julian start date for calendar reform; if not an infinity, the returned value is suitable for passing to Date#jd
:
d = Date.new(2001, 2, 3, Date::ITALY) s = d.start # => 2299161.0 Date.jd(s).to_s # => "1582-10-15" d = Date.new(2001, 2, 3, Date::ENGLAND) s = d.start # => 2361222.0 Date.jd(s).to_s # => "1752-09-14" Date.new(2001, 2, 3, Date::GREGORIAN).start # => -Infinity Date.new(2001, 2, 3, Date::JULIAN).start # => Infinity
See argument start.
Equivalent to Date#new_start
with argument Date::ENGLAND
.
Equivalent to Date#new_start
with argument Date::GREGORIAN
.