Class: Symbol

Symbol objects represent names and some strings inside the Ruby interpreter. They are generated using the :name and :"string" literals syntax, and by the various to_sym methods. The same Symbol object will be created for a given name or string for the duration of a program‘s execution, regardless of the context or meaning of that name. Thus if Fred is a constant in one context, a method in another, and a class in a third, the Symbol :Fred will be the same object in all three contexts.

   module One
     class Fred
     end
     $f1 = :Fred
   end
   module Two
     Fred = 1
     $f2 = :Fred
   end
   def Fred()
   end
   $f3 = :Fred
   $f1.object_id   #=> 2514190
   $f2.object_id   #=> 2514190
   $f3.object_id   #=> 2514190

Methods

== all_symbols id2name inspect intern to_proc to_s to_sym

Public Class methods

Symbol.all_symbols => array

Returns an array of all the symbols currently in Ruby‘s symbol table.

   Symbol.all_symbols.size    #=> 903
   Symbol.all_symbols[1,20]   #=> [:floor, :ARGV, :Binding, :symlink,
                                   :chown, :EOFError, :$;, :String,
                                   :LOCK_SH, :"setuid?", :$<,
                                   :default_proc, :compact, :extend,
                                   :Tms, :getwd, :$=, :ThreadGroup,
                                   :wait2, :$>]

Public Instance methods

sym == obj => true or false

Equality—If sym and obj are exactly the same symbol, returns true.

sym.id2name => string
sym.to_s => string

Returns the name or string corresponding to sym.

   :fred.id2name   #=> "fred"

sym.inspect => string

Returns the representation of sym as a symbol literal.

   :fred.inspect   #=> ":fred"

sym.to_sym => sym
sym.intern => sym

In general, to_sym returns the Symbol corresponding to an object. As sym is already a symbol, self is returned in this case.

sym.to_proc

Returns a Proc object which respond to the given method by sym.

  (1..3).collect(&:to_s)  #=> ["1", "2", "3"]