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Ruby | Symbol Class

Last Updated : 11 Jul, 2025
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The objects of the Symbol class represent the names present inside the Ruby interpreter. They are usually generated by using :name literal syntax or by using to_sym methods. The similar Symbol objects are created for a given name string for the duration of a program's execution, regardless of the content and meaning of the name. Example: Ruby 
# Ruby program to illustrate 
# Symbol objects

# context 3
module Geeks1

class Max
end
$a1 = :Max
end

# context 1
module Geeks2

Max = 1
$a2 = :Max
end

# context 2
def Max()

end

$a3 = :Max

puts $a1.object_id 
puts $a2.object_id 
puts $a3.object_id
Output: 
1675428
1675428
1675428
Explanation: If Max is a constant in context1, a method in context2, or class in the context3, then this :Max will be the same object in all given contexts.

Class Method

all_symbols : This method returns an array of symbols that currently present in the Ruby's symbol table. 
Symbol.all_symbols
Example: Ruby 
# Ruby program to illustrate 
# the use of all_symbol method

# Using all_symbol method
puts Symbol.all_symbols.size 
puts Symbol.all_symbols[1, 20]
Output: 
3250
"
#
$
%
&
'
(
)
*
+
,
-
.
/
:
;
<
=
>
?

Instance Methods

  1. id2name : This method returns a string that is representation of sym. 
    sym.id2name
    Example: Ruby 
    # Ruby program to illustrate 
# the use of id2name method

# Using id2name method
p :Geeks.id2name 
p :"Welcome to GeeksforGeeks Portal".id2name
    Output: 
    "Geeks"
"Welcome to GeeksforGeeks Portal"
  2. inspect : This method return the representation of sym in the form of symbol literal. 
    sym.inspect
    Example: Ruby 
    # Ruby program to illustrate 
# the use of inspect method

# Using inspect method
p :geeks.inspect
p :"welcome to geeksforgeeks portal".inspect
    Output: 
    ":geeks"
":\"welcome to geeksforgeeks portal\""
  3. to_s : This method is similar to Symbol#id2name. This method returns the name or a string that corresponding to sym. 
    sym.to_s
    Example: Ruby 
    # Ruby program to illustrate 
# the use of to_s method

# Using to_s method
p :geeks.to_s
p :"welcome to geeksforgeeks portal".to_s
    Output: 
    "geeks"
"welcome to geeksforgeeks portal"
  4. <=> :It compares sym to other_sym after calling to_s. It returns -1 if sym is less than other_sym, it returns 0 if sym is equal to other_sym, or it returns +1 if sym is greater than other_sym. 
    sym <=> other_sym
    Example: Ruby 
    # Ruby program to illustrate 
# use of <=>

# Using <=>
a= :geeks
b = :"welcome to geeksforgeeks portal"
puts a<=>b
c= :geeks
puts a<=>c
puts b<=>a
    Output: 
    -1
0
1
  5. == : It returns true if the sym is equal to obj, otherwise it return false. 
    sym== obj
    Example: Ruby 
    # Ruby program to illustrate 
# use of ==

# Using ==
a= :geeks
b = :"welcome to geeksforgeeks portal"
puts a==b
c= :geeks
puts a==c
    Output: 
    false
true
  6. [] : This method returns the value of sym.to_s[]. 
    sym[idx] --> char 
sym[b, n] --> string
  7. capitalize : This method is similar to Symbol#to_s. 
    sym.capitalize
  8. casecmp : This method is case-insensitive version of symbol <=$gt;. It will return -1, 0, 1, or nil. It is worked on A-Z/a-z, not on all Unicode. In this method nil is returned when the two symbols have incompatible encodings or if other_sym is not a symbol. 
    sym.casecmp(other)
    Example: Ruby 
    # Ruby program to illustrate 
# use of casecmp method

# Using casecmp method
puts :GeeKs.casecmp(:geeks)
puts :GeeKsGfg.casecmp(:geeksG)
puts :GeeKsGfg.casecmp(:geeksGfgz)
puts :GeeKsGfg.casecmp(3)
    Output: 
    0
1
-1
nil
  9. downcase : This method converts upper-case letters in lower-case. 
    sym.downcase
    Example: Ruby 
    # Ruby program to illustrate 
# use of the downcase method

# Using the downcase method
puts :"WELCOME TO GEEKSFORGEEKS".downcase
    Output: 
    :"welcome to geeksforgeeks"
  10. length : This method returns the length of the given sym. 
    sym.length
    Example: Ruby 
    # Ruby program to illustrate 
# use of length method

# Using length method
puts :GeeKsGfg.length
    Output: 
    8
  11. slice : This method is similar to Symbol#to_s. This method provides you character on the given index from the sym . 
    sym.slice(index)
sym.slice(b, n)
    Example: Ruby 
    # Ruby program to illustrate 
# use of slice method

# Using slice method
p :GeeKsGfg.slice(3)
p :GeeKsGfg.slice(6)
    Output: 
    "K"
"f"
  12. swapcase : This method interchange the case of the characters that present in sym. In other words, it converts lower-case into upper-case and upper-case into lower-case. 
    sym.swapcase
    Example: Ruby 
    # Ruby program to illustrate 
# use of the swapcase method

# Using swapcase method
p "WELcome TO geeksFORGEEKS".swapcase
    Output: 
    "welCOME to GEEKSforgeeks"
  13. upcase : This method converts lower-case characters into upper-case. 
    sym.upcase
    Example: Ruby 
    # Ruby program to illustrate 
# use of the upcase method

# Using upcase method
p "welcome to geeksforgeeks".upcase
    Output: 
    "WELCOME TO GEEKSFORGEEKS"
  14. to_proc : This method return a Proc object which answer to the given method by sym. 
    sym.to_proc
    Example: Ruby 
    # Ruby program to illustrate 
# use of to_proc method

# Using to_proc method
p (1..5).collect(&:to_s)
    Output: 
     ["1", "2", "3", "4", "5"]
  15. to_sym This method returns a symbol that corresponding to an object. Here sym has been already a symbol, so in this case it returns it. 
    sym.to_sym
Reference: http://ruby-doc.org/core-2.5.0/Symbol.html#method-i-5B-5D

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