[Q&A]do是什么意思?

某天某人又在某群问,do是什么意思?
google了一把,发现有个解释应该正确:
When the block is longer than one line, it's more readable to begin it with the do keyword and end it with the end keyword
看来do是block的用法,如果这个block一行写不完就可以用do...end
例如:
[1,2,3].each { |i| puts i }可写成
[1,2,3].each do |i|
   puts i
 end