ruby-on-rails - block 有什么用？

Question

请提供一个现实生活中的示例，说明如何、在何处以及为何使用block .

# Block Method
def say_hello(&block)
   puts "hello!"
   block.call
end

say_hello { puts "hello again!" }
  #=> hello!, hello again!

# Standard Method
def say_hello(block)
   puts "hello!"
   puts block
end

say_hello("hello again!")
  #=> hello!, hello again!

显然这个例子没有执行block任何正义。谢谢您的帮助!

Answer 1

people = ['bob', 'joe', 'ralph']
people.each { |person| puts "Hi, #{person}!" }