What is the set.include?(element) in Ruby?

Overview

In Ruby, we use the include() method to check if an element is a member of a particular set. An element is said to be a set member if present in the given set. The code snippet below shows how to use the include() method.

Syntax

Set.include?(element)
This line checks if `element` is a part of `Set`.

The code snippet has two main variables: Set and element. The code tests the membership of element in Set. Set.include?(element) will return true if element is a member of Set, and false otherwise.

Example

Let’s look at an example that uses include?().

# require set
require "set"
# create some sets
EvenNumbers = Set.new([2, 4, 6, 8, 10])
NumbersToTen = Set.new([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
Names = Set.new(["Amaka", "Titi"])
Workers = Set.new(["Amaka", "Chioma", "Titi"])
# check if some elements are member of a set
puts EvenNumbers.include?(2)    # true
puts NumbersToTen.include?(9)   # true
puts Names.include?("Okwudili") # false
puts Workers.include?("Paul")   # false

Explanation

  • Line 2: We import the set class.
  • Lines 5–8: We create and initialize 4 set instances.
  • Lines 11–14: We use the include?() method to check if certain elements are present in the sets created previously. Results can be seen in the console shortly after pressing the run button.

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