What is set.empty?() in Ruby?

Overview

In Ruby, we can check whether a set is empty or not by using the empty?() method. In Ruby, a set is a collection of unordered, unique and non-duplicated elements. Sometimes a set can become empty, and here is when the empty?() method comes in handy.

Syntax

set.empty?()

Parameters

set: This is the set that we want to check for emptiness.

Return value

The value returned is a boolean. If the set is empty, then true is returned. Otherwise, false is returned.

Example

# require the set class
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])
Workers = Set.new(["Amaka", "Chioma", "Titi"])
EmptySet = Set.new([])
# clear a particular set
NumbersToTen.clear
# check if sets are empty
puts EvenNumbers.empty?()  # false
puts NumbersToTen.empty?() # true
puts Workers.empty?()      # false
puts EmptySet.empty?()     # true

Explanation

  • Line 2: We require the set class.
  • Lines 5–8: We created some set instances, one of which is an empty set.
  • Line 11: We use the clear method to clear or empty the NumbersToTen set.
  • Lines 14–17: Using the empty?() method, we check each set to determine whether it is empty or not. We print the corresponding results to the console.

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