[程式] Rails Tips

• 擷取前N個字元 - truncate(text, options = {}, &block)
  Definition-
  Truncates a given text after a given :length if text is longer than :length (defaults to 30). The last characters will be replaced with the :omission (defaults to “…”) for a total length not exceeding :length.
  
  • Pass a :separator to truncate text at a natural break.
  • Pass a block if you want to show extra content when the text is truncated.
  • The result is marked as HTML-safe, but it is escaped by default, unless :escape is false. Care should be taken if text contains HTML tags or entities, because truncation may produce invalid HTML (such as unbalanced or incomplete tags).
  ex.
  
  truncate("Once upon a time in a world far far away")
  # => "Once upon a time in a world..."
  truncate("Once upon a time in a world far far away", length: 17)
  # => "Once upon a ti..."
  truncate("Once upon a time in a world far far away", length: 17, separator: ' ')
  # => "Once upon a..." truncate("And they found that many people were sleeping better.", length: 25, omission: '... (continued)')
  # => "And they f... (continued)"
  truncate("<p>Once upon a time in a world far far away</p>")
  # => "<p>Once upon a time in a wo..."
  Ref: http://api.rubyonrails.org/classes/ActionView/Helpers/TextHelper.html#method-i-truncate