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Hash.include?() Method with Example in Ruby

Ruby Hash.include?() Method: Here, we are going to learn about the Hash.include?() Method with examples in Ruby programming language.
Submitted by Hrithik Chandra Prasad, on February 15, 2020

Hash.include?() Method

In this article, we will study about Hash.include?() Method. The working of the method can't be assumed because of it's quite a different name. Let us read its definition and understand its implementation with the help of syntax and program codes.

Method description:

This method is a Public instance method and belongs to the Hash class which lives inside the library of Ruby language. This method is used to check whether a key is a part of the particular Hash instance or not. It will search through the whole Hash and gives you the result according to its search. Let us go through the syntax and demonstrating the program codes of this method.

If you are thinking about what it will return then let me tell you, it will return a Boolean value. The returned value will be true if it finds the key inside the Hash and the return value will be false if it does not find the key to be the part of Hash instance.

Syntax:

    Hash_instance.include?(key)

Argument(s) required:

This method only takes one parameter and that argument is nothing but a key whose presence we want to check.

Example 1:

=begin
  Ruby program to demonstrate Hash.include method
=end	

hsh = {"colors"  => "red",
     "letters" => "a", "Fruit" => "Grapes"}

puts "Hash.include implementation:"

puts "Enter the Key you want to search:"
ky = gets.chomp

if (hsh.include?(ky))
	puts "Key found successfully"
else
	puts "Key not found!"
end

Output

Hash.include implementation:
Enter the Key you want to search:
 colors
Key found successfully

Explanation:

In the above code, you can observe that we are invoking the include method on the normal Hash instance. It has returned true when it found the presence of the key in the Hash object which is entered by the user.

Example 2:

=begin
  Ruby program to demonstrate Hash.include method
=end	

hsh = {"colors"  => "red",
     "letters" => "a", "Fruit" => "Grapes"}

hsh1 = {"cars"  => "800",
     "bike" => "pulsar", "phone" => "A50"}

hsh2 = {"one"=> hsh, "two" => hsh1}

puts "Hash.include implementation:"

puts "Enter the Key you want to search:"
ky = gets.chomp

if (hsh2.include?(ky))
	puts "Key found successfully"
else
	puts "Key not found!"
end

Output

RUN 1:
Hash.include implementation:
Enter the Key you want to search:
 bike
Key not found!

RUN 2:
Hash.include implementation:
Enter the Key you want to search:
 two
Key found successfully

Explanation:

In the above program, you can verify that include method does not work upon Hash instance which is the collection of multiple Hash instances. It will return false even if the object is a part of the Hash instance.