How to sum array of numbers in Ruby?

For ruby >= 2.4 you can use sum:

array.sum

For ruby < 2.4 you can use inject:

array.inject(0, :+)

Note: the 0 base case is needed otherwise nil will be returned on empty arrays:

> [].inject(:+)
nil
> [].inject(0, :+)
0

Try this:

array.inject(0){|sum,x| sum + x }

See Ruby's Enumerable Documentation

(note: the 0 base case is needed so that 0 will be returned on an empty array instead of nil)

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