Hidden features of Ruby

Questions

Continuing the "Hidden features of ..." meme, let s share the lesser-known but useful features of Ruby programming language.

Try to limit this discussion with core Ruby, without any Ruby on Rails stuff.

See also:

http://stackoverflow.com/questions/9033/hidden-features-of-c http://stackoverflow.com/questions/9033/hidden-features-of-c http://stackoverflow.com/questions/15496/hidden-features-of-java http://stackoverflow.com/questions/15496/hidden-features-of-java http://stackoverflow.com/questions/61088/hidden-features-of-javascript http://stackoverflow.com/questions/61088/hidden-features-of-javascript http://stackoverflow.com/questions/709679/hidden-features-of-ruby-on-rails http://stackoverflow.com/questions/709679/hidden-features-of-ruby-on-rails http://stackoverflow.com/questions/101268/hidden-features-of-python http://stackoverflow.com/questions/101268/hidden-features-of-python

(Please, just one hidden feature per answer.)

Thank you

Answers

From Ruby 1.9 Proc#=== is an alias to Proc#call, which means Proc objects can be used in case statements like so:

def multiple_of(factor)
  Proc.new{|product| product.modulo(factor).zero?}
end

case number
  when multiple_of(3)
    puts "Multiple of 3"
  when multiple_of(7)
    puts "Multiple of 7"
end

Source

License : cc by-sa 3.0

http://stackoverflow.com/questions/63998/hidden-features-of-ruby

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