21 天Ruby-------- loop

class ForLoop

  def callFor 
    for i in 1..3
      print "index = #{i}\n"
    end
  end

  def callWhile
    a = 1
    a *= 2 while a < 10
    puts a

    a -= 2 until a < 0
    puts a
  end

  def callWhile2
    a = 1
    a += 1  while a < 5
    puts a
  #  print "index = #{a}\n"
  end

  def time
    3.times do
      print "Ho! "
    end
  end

  def upto
     1.upto(3) do |x|
      puts x
    end
  end

  def step
    0.step(10, 2) do |x|
      puts x
    end
  end

  def each 
    [1, 2, 3, 4, 5].each do |x|
      puts x
    end
  end

  def callFor2  # seems similar as each
    for n in [5, 4, 3, 2, 1]
      puts n
    end
  end

  def callLoop
     i = 0
     loop do
      i += 1
      puts i
      next if not i > 3
      puts "i > 3"
      redo if i >= 6 and i <= 9
      puts "i < 6 or i > 9"
      break if i == 10 
    end
  end

end

instance = ForLoop.new
instance.callFor
print "----------\n"
instance.callWhile2
print "----------\n"
instance.time
print "\n----------\n"
instance.upto
print "----------\n"
instance.step
print "----------\n"
instance.each
print "----------\n"
instance.callFor2
print "----------\n"
instance.callLoop

# output
#index = 1
#index = 2
#index = 3
#----------
#5
#----------
#Ho! Ho! Ho! 
#----------
#1
#2
#3
#----------
#0
#2
#4
#6
#8
#10
#----------
#1
#2
#3
#4
#5
#----------
#5
#4
#3
#2
#1
#----------
#1
#2
#3
#4
#i > 3
#i < 6 or i > 9
#5
#i > 3
#i < 6 or i > 9
#6
#i > 3
#7
#i > 3
#8
#i > 3
#9
#i > 3
#10
#i > 3
#i < 6 or i > 9

ruby loop变现形式真多