Ruby From Beginning
Hello World
#!/usr/bin/ruby puts "Hello World!"
What is your name?
#!/usr/bin/ruby print "What is your name? " name = gets puts "Your name is #{name}"
Heredocument
#!/usr/bin/ruby print <<EOF This is the first way of creating here document ie. multiple line string. EOF
ARGS from the Console
#!/usr/bin/ruby puts ARGV[0] puts ARGV[1] puts ARGV[2]
Read a file
#!/usr/bin/ruby puts "What file do you want to read? " Filename = gets Filename.delete!("\n") TheFile = File.read( Filename ) puts TheFile.to_s
Write in a file
#!/usr/bin/ruby puts "write" VarFile = File.new("dat.txt", "w+") VarFile.puts "das erste " VarFile.puts "das zweite" VarFile.close
IF Statement
#!/usr/bin/ruby puts "Number?: " x = gets if x.to_i > 2 puts "x is greater than 2" elsif x.to_i <= 2 and x.to_i != 0 puts "x is 1" else puts "I can't guess the number" end
CASE Statement
#!/usr/bin/ruby print "Enter your grade: " grade = gets.chomp case grade when "A" puts 'You pretty smart!' when "B" puts 'You smart!' when "C", "D" puts 'You pretty dumb!!' else puts "You can't even use a computer!" end
WHILE Statement
#!/usr/bin/ruby $i = 0 $num = 5 while $i < $num do puts("Inside the loop i = #$i" ) $i +=1 end
FOR Statement
#!/usr/bin/ruby for i in 0..5 puts "Value of local variable is #{i}" end
OR
#!/usr/bin/ruby (0..5).each do |i| puts "Value of local variable is #{i}" end
Methods
#!/usr/bin/ruby def test(a1 = "Ruby", a2 = "Perl") puts "The programming language is #{a1}" puts "The programming language is #{a2}" end
Class
#!/usr/bin/ruby class Sample def hello puts "Hello Ruby!" end end
Instance of a class
object = Sample.new object.hello
Everything is a class
1.upto(3) { |i| puts i } # 1 2 3 3.downto(1) { |i| puts i } # 3 2 1 0.step(10,2) { |i| puts i } # 0 2 4 6 8 10 3.times { puts "42" } # 42 42 42