From: Jason Lillywhite <jason.lillywhite@...>
Date: 2009-07-29T12:39:26+09:00
Subject: previous value in array block

Is this a good way to use a previous value in an array block?

I want to subtract the item(i) from item(i-1) of the array, a and return
a new array of the results. Below is my attempt.

a = [1,3,3,2]
prev_item = 0
b = []

a.each do |item|
  b << item - prev_item
  prev_item = item
end

puts b

=> 1,2,0,-1

I'm thinking there must be a more elegant way of doing this.

thank you!
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