From: Mike Berrow <mberrow1@...>
Date: 2006-07-05T17:07:38+09:00
Subject: Re: Parallel Array

# Here is another variation (using Symbol#to_proc)
class Symbol
  def to_proc
    Proc.new { |obj, *args| obj.send(self, *args) }
  end
end

class Array
  def c2(a) # parallel collect
    (0 .. size - 1).collect {|i| yield self[i], a[i]}
  end
  def c2op(a,opb)
    c2(a,&opb)
  end
end

# Use with a following block
p [4,3,2,1].c2([2,2,2,2]) {|a,b| a+b}
# => [6, 5, 4, 3]

# or just send the desired operator as a symbol
a=[4,3,2,1]
b=[2,2,2,2]
p a.c2op(b, :+)
# => [6, 5, 4, 3]

# ... or even re-define addition, subtraction etc.
class Array
  def +(b)
    self.c2op(b, :+)
  end
  def -(b)
    self.c2op(b, :-)
  end
end

a=[4,3,2,1]
b=[2,2,2,2]
p a + b
# => [6, 5, 4, 3]
p a - b
# => [2, 1, 0, -1]

-- Mike Berrow

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