# bad
  email_with_name = user.name + ' <' + user.email + '>'

  # good
  email_with_name = "#{user.name} <#{user.email}>"

  # good
  email_with_name = format('%s <%s>', user.name, user.email)

  "#{ user.last_name }, #{ user.first_name }"

  "#{ user.last_name }, #{ user.first_name }"

    # bad
    name = "Bozhidar"

    # good
    name = 'Bozhidar'

    # bad
    name = 'Bozhidar'

    # good
    name = "Bozhidar"

 # bad
  char = "htmlcode">

 class Person
   attr_reader :first_name, :last_name

   def initialize(first_name, last_name)
    @first_name = first_name
    @last_name = last_name
   end

   # bad - valid, but awkward
   def to_s
    "#@first_name #@last_name"
   end

   # good
   def to_s
    "#{@first_name} #{@last_name}"
   end
  end

  $global = 0
  # bad
  puts "$global = #$global"

  # good
  puts "$global = #{$global}"




    在对象插值的时候不要使用 Object#to_s，它将会被自动调用。


  # bad
  message = "This is the #{result.to_s}."

  # good
  message = "This is the #{result}."




    操作较大的字符串时, 避免使用 String#+ 做为替代使用 String#<<。就地级联字符串块总是比 String#+ 更快，它创建了多个字符串对象。


  # good and also fast
  html = ''
  html << '<h1>Page title</h1>'

  paragraphs.each do |paragraph|
   html << "<p>#{paragraph}</p>"
  end




    When using heredocs for multi-line strings keep in mind the fact

    that they preserve leading whitespace. It's a good practice to

    employ some margin based on which to trim the excessive whitespace.

    heredocs 中的多行文字会保留前缀空白。因此做好如何缩进的规划。这是一个很好的

    做法，采用一定的边幅在此基础上削减过多的空白。


  code = <<-END.gsub(/^\s+\|/, '')
   |def test
   | some_method
   | other_method
   |end
  END
  #=> "def test\n some_method\n other_method\nend\n"