Playing around with irb

play with irb

vagrant [day_2]> irb
2.1.3 :001 > puts "hello"
hello
 => nil
2.1.3 :002 > "khurram".reverse
 => "marruhk"
2.1.3 :003 > ramon
NameError: undefined local variable or method `ramon' for main:Object
	from (irb):3
	from /usr/local/rvm/rubies/ruby-2.1.3/bin/irb:11:in `<main>'
2.1.3 :004 > "ramon".reverse
 => "nomar"
2.1.3 :005 > quit
vagrant [day_2]> ls
lecture_2.txt
vagrant [day_2]> touch ruby.rb
vagrant [day_2]> ls
lecture_2.txt  ruby.rb
vagrant [day_2]> ls
lecture_2.txt  ruby.rb
vagrant [day_2]> ruby ruby.rb
Enter your name: ramon
hello ramon
vagrant [day_2]> irb
2.1.3 :001 > def say_hi
2.1.3 :002?>   end
 => :say_hi
2.1.3 :003 > def say_hi
2.1.3 :004?>   end
 => :say_hi
2.1.3 :005 > def say_hi(name)
2.1.3 :006?>   puts "Hi #{nam}"
2.1.3 :007?>   end
 => :say_hi
2.1.3 :008 > say_hi(ramon)
NameError: undefined local variable or method `ramon' for main:Object
	from (irb):8
	from /usr/local/rvm/rubies/ruby-2.1.3/bin/irb:11:in `<main>'
2.1.3 :009 > say_hi("ramon")
NameError: undefined local variable or method `nam' for main:Object
	from (irb):6:in `say_hi'
	from (irb):9
	from /usr/local/rvm/rubies/ruby-2.1.3/bin/irb:11:in `<main>'
2.1.3 :010 > def say_hi(name)
2.1.3 :011?>   puts "Hi #{name}"
2.1.3 :012?>   end
 => :say_hi
2.1.3 :013 > say_hi("ramon")
Hi ramon
 => nil
2.1.3 :014 > s = "ramon"
 => "ramon"
2.1.3 :015 > s.inspect
 => "\"ramon\""
2.1.3 :016 > s.class
 => String
2.1.3 :017 > s.length
 => 5
2.1.3 :018 > s.average
NoMethodError: undefined method `average' for "ramon":String
	from (irb):18
	from /usr/local/rvm/rubies/ruby-2.1.3/bin/irb:11:in `<main>'
2.1.3 :019 > s.collect
NoMethodError: undefined method `collect' for "ramon":String
	from (irb):19
	from /usr/local/rvm/rubies/ruby-2.1.3/bin/irb:11:in `<main>'
2.1.3 :020 > arr = [2,2,22,222]
 => [2, 2, 22, 222]
2.1.3 :021 > arr.inspect
 => "[2, 2, 22, 222]"
2.1.3 :022 > arrr.class
NameError: undefined local variable or method `arrr' for main:Object
	from (irb):22
	from /usr/local/rvm/rubies/ruby-2.1.3/bin/irb:11:in `<main>'
2.1.3 :023 > arr.class
 => Array
2.1.3 :024 > arr.sort
 => [2, 2, 22, 222]
2.1.3 :025 > arr
 => [2, 2, 22, 222]
2.1.3 :026 > arr.reverse
 => [222, 22, 2, 2]
2.1.3 :027 > arr
 => [2, 2, 22, 222]
2.1.3 :028 > arr.reverse!
 => [222, 22, 2, 2]
2.1.3 :029 > arr
 => [222, 22, 2, 2]
2.1.3 :030 > arr.each do |element|
2.1.3 :031 >     puts element
2.1.3 :032?>   end
222
22
2
2
 => [222, 22, 2, 2]
2.1.3 :033 > Math.sqrt(9)
 => 3.0
2.1.3 :034 > Time.now
 => 2015-03-03 22:05:10 +0000
2.1.3 :035 > Array.new(10,'bee')
 => ["bee", "bee", "bee", "bee", "bee", "bee", "bee", "bee", "bee", "bee"]
2.1.3 :036 > include Math
 => Object
2.1.3 :037 > sqrt 64
 => 8.0