ruby range with output based on multiples of 3, 5, 15

range_multiples.rb

# frozen_string_literal: true

require 'benchmark'

# synopsis
#
# rubocop suggested syntax is
#   * costlier on execution
#   * not really that super easy to read and maintain than case statement
#   * adds more number of lines
#   * `zero?` is syntactical-sugar but high cost on execution
# case statement
#   * is fastest in execution
#   * seems most suitable for production
# one-liner
#   * is just a show-off :)
#   * but it does work too!

# sample output:
#
# 1 2 Ping 4 Pong Ping 7 8 Ping Pong 11 Ping 13 14 PingPong 16 17 Ping 19 Pong
# Ping 22 23 Ping Pong 26 Ping 28 29 PingPong 31 32 Ping 34 Pong Ping 37 38 Ping
# Pong 41 Ping 43 44 PingPong 46 47 Ping 49 Pong Ping 52 53 Ping Pong 56 Ping 58
# 59 PingPong 61 62 Ping 64 Pong Ping 67 68 Ping Pong 71 Ping 73 74 PingPong 76
# 77 Ping 79 Pong Ping 82 83 Ping Pong 86 Ping 88 89 PingPong 91 92 Ping 94 Pong
# Ping 97 98 Ping Pong
#
# Benchmarks
#
# Rehearsal ------------------------------------------------------------
# one liner                  0.026752   0.000098   0.026850 (  0.026848)
# one liner (rubocop)        0.031388   0.000084   0.031472 (  0.031474)
# case statement             0.026730   0.000095   0.026825 (  0.026840)
# case statement (rubocop)   0.030073   0.000081   0.030154 (  0.030189)
# --------------------------------------------------- total: 0.115301sec
#
#                                user     system      total        real
# one liner                  0.027161   0.000050   0.027211 (  0.027212)
# one liner (rubocop)        0.030034   0.000046   0.030080 (  0.030083)
# case statement             0.026946   0.000100   0.027046 (  0.027059)
# case statement (rubocop)   0.031117   0.000055   0.031172 (  0.031173)

#
# One-liner ruby statement. Complex to maintain. Not ideal.
#
# @param [Range] range -> ruby object
#
# @return [String] concatenated string of final output
#
def ping_pong_one_liner(range = 1..100)
  return 'Hey! I am smart :) Give me a range' unless range.is_a?(Range)

  range.map {|e| e % 15 == 0 ? 'PingPong' : (e % 5 == 0 ? 'Pong' : (e % 3 == 0 ? 'Ping' : e )) }.join(' ')
end

#
# Using case statement. Easier to maintain than one-liner
#
# @param [Range] range -> ruby object
#
# @return [String] concatenated string of final output
#
def ping_pong_case(range = 1..100)
  return 'Hey! I am smart :) Give me a range' unless range.is_a?(Range)

  range.map do |e|
    case
    when e % 15 == 0 then 'PingPong'
    when e %  5 == 0 then 'Pong'
    when e %  3 == 0 then 'Ping'
    else
      e
    end
  end.join(' ')
end

#
# One-liner ruby statement, corrected with rubocop
#
# @param [Range] range -> ruby object
#
# @return [String] concatenated string of final output
#
def ping_pong_one_liner_rubocop(range = 1..100)
  return 'Hey! I am smart :) Give me a range' unless range.is_a?(Range)

  range.map do |e|
    if (e % 15).zero?
      'PingPong'
    else
      (if (e % 5).zero?
         'Pong'
       else
         ((e % 3).zero? ? 'Ping' : e)
       end)
    end
  end.join(' ')
end

#
# Using case statement, corrected with rubocop
#
# @param [Range] range -> ruby object
#
# @return [String] concatenated string of final output
#
def ping_pong_case_rubocop(range = 1..100)
  return 'Hey! I am smart :) Give me a range' unless range.is_a?(Range)

  range.map do |e|
    if (e % 15).zero?
      'PingPong'
    elsif (e %  5).zero?
      'Pong'
    elsif (e %  3).zero?
      'Ping'
    else
      e
    end
  end.join(' ')
end

# run
#
puts ping_pong_one_liner(1..100)

puts "\nBenchmarks\n\n"
Benchmark.bmbm do |x|
  x.report('one liner') { 1000.times { ping_pong_one_liner(1..100) } }
  x.report('one liner (rubocop)') { 1000.times { ping_pong_one_liner_rubocop(1..100) } }
  x.report('case statement') { 1000.times { ping_pong_case(1..100) } }
  x.report('case statement (rubocop)') { 1000.times { ping_pong_case_rubocop(1..100) } }
end