From: Marko Schulz <in6x059@...>
Date: 2001-04-28T19:35:25+09:00
Subject: [ruby-talk:14371] Re: RCR: Array#insert

On Sat, Apr 28, 2001 at 12:00:58PM +0900, TAKAHASHI Masayoshi wrote:
>
> Another candidate is:
> 
> [ Another possible implementation of Array#insert ]

I would actually prefer an version that is able to insert more than
one element, just like push can add more than one element at the
end. So here is my take:


  class Array 
    def insert(pos, *elem)
      self[pos,0] = elem
      self
    end
  end


  a=[1,2,3,4,5,6]
    ==>[1, 2, 3, 4, 5, 6]
  a.insert(2,"new")
    ==>[1, 2, "new", 3, 4, 5, 6]
  a.insert(5,"two","entries")
    ==>[1, 2, "new", 3, 4, "two", "entries", 5, 6]
  a.insert(0, "At","the","start")  # Similar to unshift, but with more elements
    ==>["At", "the", "start", 1, 2, "new", 3, 4, "two", "entries", 5, 6]


I also pondered about a variant that handles negativ indeces a bit
different: -1 inserts after the last element, -2 before the last, -3
before the last but one ...:


  class Array 
    def insert(pos, *elem)
      if pos == -1
        pos = self.length
      elsif pos < 0
        pos += 1
      end
       
      self[pos,0] = elem

      self
    end
  end


  a=[1,2,3,4,5,6]
    ==>[1, 2, 3, 4, 5, 6]
  a.insert(-1,"end")                # Similar to push
    ==>[1, 2, 3, 4, 5, 6, "end"]
  a.insert(-2,*%w(just before the))
    ==>[1, 2, 3, 4, 5, 6, "just", "before", "the", "end"]


-- 
marko schulz

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