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Array#pad! (See related posts)

My ri docco says there is an Array#pad! but runtime Ruby says there isn't. Bah. So I wrote one:

   1  
   2  class Array
   3    def pad!(expected_length, pad_item = nil)
   4      while expected_length > length
   5        self << pad_item
   6      end
   7      self
   8    end
   9  end
to ruby array pad padding by nicwilliams on Mon Apr 07 06:44:20 -0400 2008

Comments on this post

nicwilliams posts on Apr 07, 2008 at 06:48
Actually now I put it in a module and include it: http://pastie.caboo.se/176445
alxx posts on Apr 07, 2008 at 11:26
Here's something even lighter:

   1  
   2  class Array
   3   def pad!(expected_length, pad_item = nil)
   4     expected_length.times { self << pad_item }
   5     self
   6   end
   7  end


But there's not much point, because there IS actually a padding method for Ruby arrays. Therefore, you can simply do:

   1  
   2   x = [1, 2, 3]
   3   
   4   # Instead of x.pad!('pad', 4)
   5   x.fill 'pad', x.length, 4
alxx posts on Apr 07, 2008 at 11:35
Minor typo: with your naming convention, the first example would need (expected_length - length).times
ChronicStar posts on Apr 07, 2008 at 23:23
If you just want to pad with nil, how about this:

   1  x = [1,2,3]
   2  # Padding to 10 elements total:
   3  x[9] ||= nil
   4  #=> [1, 2, 3, nil, nil, nil, nil, nil, nil, nil]


That will modify the array in place, of course. You can use dup to get around that if you want.

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