20 minutes Ruby

ref:https://www.ruby-lang.org/en/documentation/quickstart/

#!/usr/bin/env rubyclass megagreeter Attr_accessor:names # Create The object def initialize (names = "World") @names      = Names End # Say hi to everybody def say_hi if @names. Nil? Puts "..." elsif @names. respond_to?      ("Each") # @names is a list of some kind, iterate!        @names. Each do |name|      Puts "Hello #{name}!"    End else puts "Hello #{@names}!"      End END # Say bye to everybody def Say_bye if @names. Nil? Puts "..." elsif @names. respond_to?  ("join") # Join the list elements with commas puts "Goodbye #{@names. Join (", ")}.    Come back soon! "  Else puts "Goodbye #{@names}.    Come back soon! "  End Endendif __file__ = = $ mg = megagreeter.new Mg.say_hi Mg.say_bye # change name to be "Zeke" mg.names = "Zeke" Mg.say_hi Mg.say_bye # Change the name to an array of names mg.names = ["Albert", "Brenda", "Charles", "Da VE "," Engelbert "] mg.say_hi Mg.say_bye # change to nil mg.names = nil Mg.say_hi mG.say_byeend 

1. Attr_accseeor:name

The return value (Array) for megagreeter.instance_methods false is many: id:id= two items

Mg.respond_to? : ID or mg.respond_to? (" ID ")

mg.respond_to?: id= or mg.respond_to? (" Id= ") is True

2. Use the object's properties instead of the object's type to determine how to execute

@names. respond_to?

3. __file__==$0

20 minutes Ruby