I've got two (or more) arrays with 12 integers in each (corresponding to values for each month). All I want is to add them together so that I've got a single array with summed values for each month. Here's an example with three values: [1,2,3] and [4,5,6] => [5,7,9]
The best I could come up with was:
[[1,2,3],[4,5,6]].transpose.map{|arr| arr.inject{|sum, element| sum+element}} #=> [5,7,9]
Is there a better way of doing this? It just seems such a basic thing to want to do.
here's my attempt at code-golfing this thing:
// ruby 1.9 syntax, too bad they didn't add a sum() function afaik
[1,2,3].zip([4,5,6]).map {|a| a.inject(:+)} # [5,7,9]
zip returns [1,4], [2,5], [3,6], and map sums each sub-array.
Here's the transpose version Anurag suggested:
a.transpose.map {|x| x.reduce(:+)}
This will work with any number of component arrays. reduce and inject are synonyms, but reduce seems to me to more clearly communicate the code's intent here...