Special method in ruby (question mark)

Question

How do you define a method of verification? The example: include? even? odd?

>> 2.odd?
=> false
>> 6.even?
=> true
>>

See http://stackoverflow.com/questions/1345843/ruby-question-mark — tjmw, Feb 07 '11 at 20:56

score 10 · Answer 1 · answered Feb 07 '11 at 20:54

10

The same way you define any other function - the question mark is part of the function name:

def is_it?
    return (...)
end

Cheers!

answered Feb 07 '11 at 20:54

Xavier Holt

score 5 · Accepted Answer · answered Feb 07 '11 at 21:02

5

class Integer
  def is_even?  
    self.remainder(2) == 0
    # this is either true or false, just what we want
  end
end

p 4.is_even?
#=> true

answered Feb 07 '11 at 21:02

steenslag

2 Answers2