How to sum array members in Ruby?

Question

1

I have an array of integers.

For example:

array = [123,321,12389]

Is there any nice way to get the sum of them?

I know, that

sum = 0
array.each { |a| sum+=a }

would work.

Mike Woodhouse
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asked Oct 8 '09 at 16:04

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zenazn · Answer 1 · 2009-10-08 16:07:04Z

Try this:

array.inject{|sum,x| sum + x }

answered Oct 8 '09 at 16:07

zenazn
2,835915

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jorney's array.inject(:+) is more efficient. – Peter Oct 9 '09 at 7:09

jrhicks · Answer 2 · 2009-10-08 18:29:42Z

Add sum to the Array class

class Array
    def sum
        self.inject{|sum,x| sum + x }
    end
end

Then do fun stuff like:

[1,2,3,4].sum

Mike Woodhouse · Answer 3 · 2009-10-08 16:49:10Z

Alternatively (just for comparison), if you have Rails installed (actually just ActiveSupport):

require 'activesupport'
array.sum

jomey · Answer 4 · 2009-10-08 16:28:13Z

Or try the ruby 1.9 way

array.inject(:+)

answered Oct 8 '09 at 16:28

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Also works with 1.8.7 – glenn jackman Oct 8 '09 at 16:29

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Also works with Rails – khelll Oct 8 '09 at 18:30

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beautiful, you made my day – marcgg Dec 23 '09 at 13:39

ruby inject sum