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ary = [1,2,3]

ary.each do |item|
     # 这里就是块
     puts item
end

(1..5).each { |i| puts 2 * i }
# { |i| puts 2 * i } 为块

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class User
  REGION = "china"
  $time = Time.now #全局变量，跨类使用
  @@id= 0 #类变量，类的属性,实例对象中共享
  @age = 18 # 实例变量,类中所有方法内共享
  def initialize (name,age=18) # name、age为局部变量,仅在该方法内使用
    print "我是局部变量name\n"
    @@id += 1
    @name = name
    @age = age
  end

  def display
    puts "id:#{@@id}"
    puts "name:#{@name}"
    puts "age:#{@age}"
    puts "region:#{REGION}"
    puts '-------'
  end

  def test
    puts "同类方法调另外一个方法定义的实例变量@age,#{@age}"
    puts "调用常量REGION:#{REGION}"
  end

end

class OtherClass

  def nowtime
    print "我是全局变量$time，可以跨类访问，值为#{$time}\n"
  end
end


user1 = User.new("Jason")
user1.display
user1.test

user2 = User.new('Cherry',19)
user2.display

timeobj = OtherClass.new
timeobj.nowtime