[ruby-talk:13597] Re: All In A Row?

On Tue, 10 Apr 2001 03:15:47 GMT, John Kaurin pontificated:
+ Is there a Ruby method for arrays that will determine if all of the elements
+ are in a sequence?
+ 
+ Something like:
+ 
+ [1, 2, 3, 4].sequence? -> true
+ [1, 3, 4, 5].sequence? -> false
+ 
+ ["a", "b", "c", "d"].sequence? -> true
+ ["a", "c", "d", "e"].sequence? -> false
+ 
+ Maybe extrapolated to take an argument:
+ 
+ [1, 3, 5, 7].sequence?(2) -> true
+ [1, 5, 7, 9].sequence?(2) -> false
+ 
+ ["a", "c", "e", "g"].sequence?(2) -> true
+ ["a", "e", "g", "i"].sequence?(2) -> false

when you design your own you could pass it a block

class Array
  def seq?
    return true if length <= 1
    for i in (0..length-2).to_a
       return false unless yield (self[i]) == self[i+1]
    end
    true
  end
end

a = [1,2,3,4,5]
p a.seq? {|x| x + 1}  		#true
b = [1,3,9,27]
p b.seq? {|x| x + 1}  		#false
p b.seq? {|x| x * 3}  		#true
p [1,0].seq? {|x| Math.log x} 	#true
c = %w(a b c d e f)
p c.seq? {|x| x.succ} 		#true

-- 
ruby -F- -e '$, = $; . sub /./, % \ Another\  ; print %w.Just Rewbie .. join'