method

try

Ruby on Rails latest stable (v2.3.8) - 3 notes - Class: Object

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What's this?

try(method, *args, &block) public

Invokes the method identified by the symbol method, passing it any arguments and/or the block specified, just like the regular Ruby Object#send does.

Unlike that method however, a NoMethodError exception will not be raised and nil will be returned instead, if the receiving object is a nil object or NilClass.

Examples

Without try

  @person && @person.name

  @person ? @person.name : nil

With try

  @person.try(:name)

try also accepts arguments and/or a block, for the method it is trying

  Person.try(:find, 1)
  @people.try(:collect) {|p| p.name}

Show source

# File activesupport/lib/active_support/core_ext/try.rb, line 25
  def try(method, *args, &block)
    send(method, *args, &block)
  end

January 6, 2010

2 thanks

Doesn't return nil if the object you try from isn't nil.

Note that this doesn’t prevent a NoMethodError if you attempt to call a method that doesn’t exist on a valid object.

  a = Article.new

  a.try(:author) #=> #<Author ...>

  nil.try(:doesnt_exist) #=> nil

  a.try(:doesnt_exist) #=> NoMethodError: undefined method `doesnt_exist' for #<Article:0x106c7d5d8>