sum(identity = 0, &block)
Instance Public methods
Calculates a sum from the elements.
1 2 | payments.sum { |p| p.price * p.tax_rate }payments.sum(&:price) |
The latter is a shortcut for:
1 | payments.inject(0) { |sum, p| sum + p.price } |
It can also calculate the sum without the use of a block.
1 2 3 | [5, 15, 10].sum # => 30['foo', 'bar'].sum # => "foobar"[[1, 2], [3, 1, 5]].sum => [1, 2, 3, 1, 5] |
The default sum of an empty list is zero. You can override this default:
1 | [].sum(Payment.new(0)) { |i| i.amount } # => Payment.new(0) |
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