How to Check the Data Type of a Variable in Ruby?

In this article, we will discuss how to check the data type of a variable in Ruby. We can check the data types of a variable through different methods ranging from class to kind_of method in Ruby.

Using Class method

The Class method returns the class name of an object.

Syntax:

variable.class

Example: 

In this example, we use the class method on num,string and an array to determine its data type, which returns Integer.

Ruby

# Check the Data Type of a Variable using 'class' method
# Example 1: Integer
num = 10
puts "Data type of 'num': #{num.class}"  

# Example 2: String
str = "GeeksforGeeks"
puts "Data type of 'str': #{str.class}"  

# Example 3: Array
arr = [1, 2, 3]
puts "Data type of 'arr': #{arr.class}"  

Output

Data type of 'num': Integer
Data type of 'str': String
Data type of 'arr': Array

Using is_a? Method

The is_a? method is used to check if an object is an instance of a specific class or its subclass.

Syntax:

variable.is_a?(ClassName)

Example: 

In this example we use the is_a? method on num,string and array to check if it is an instance of the Integer,string and array class.The method returns true if num,str,array are instance of Integer,string and array, otherwise false.

Ruby

# Check the Data Type of a Variable  Using 'is_a?' method
 
# Example 1: Integer
num = 10
# Checking if 'num' is an Integer
puts "Is 'num' an Integer? #{num.is_a?(Integer)}"  

# Example 2: String
str = "GeeksforGeeks"

# Checking if 'str' is a String
puts "Is 'str' a String? #{str.is_a?(String)}"  

# Example 3: Array
arr = [1, 2, 3]
puts "Is 'arr' an Array? #{arr.is_a?(Array)}"  

Output

Is 'num' an Integer? true
Is 'str' a String? true
Is 'arr' an Array? true

Using kind_of? Method

The kind_of? method is used to check if an object is an instance of a specific class or its subclass.The method returns true if num,str,array are instance of Integer,string and array, otherwise false.

Syntax:

variable.kind_of?(ClassName)

Example: 

In this example we use the kind_of? method on num,str,arr to check if it is an instance of the integer,string and array class.

Ruby

# Check the Data Type of a Variable Using 'kind_of?' method
# Example 1: Integer
num = 10
puts "Is 'mum' an integer? #{num.kind_of?(Integer)}" # Output: Is 'num' an Integer? true

# Example 2: String
str = "GeeksforGeeks"
puts "Is 'str' a String? #{str.kind_of?(String)}" # Output: Is 'str' a String? true

# Example 3: Array
arr = [1, 2, 3]
# Checking if 'arr' is an Array
puts "Is 'arr' an Array? #{arr.kind_of?(Array)}"  # Output: Is 'arr' an Array? true

Output

Is 'mum' an integer? true
Is 'str' a String? true
Is 'arr' an Array? true