diff options
| -rw-r--r-- | activesupport/CHANGELOG | 5 | ||||
| -rw-r--r-- | activesupport/lib/active_support/core_ext/enumerable.rb | 17 | ||||
| -rw-r--r-- | activesupport/test/core_ext/enumerable_test.rb | 26 |
3 files changed, 38 insertions, 10 deletions
diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG index ed820edd73..e1d34edb90 100644 --- a/activesupport/CHANGELOG +++ b/activesupport/CHANGELOG @@ -1,10 +1,11 @@ *SVN* -* Added Enumerable#sum for calculating a sum from the elements [DHH]. Examples: +* Added Enumerable#sum for calculating a sum from the elements [DHH, jonathan@daikini.com]. Examples: + [1, 2, 3].sum payments.sum { |p| p.price * p.tax_rate } payments.sum(&:price) - + This is instead of payments.inject(0) { |sum, p| sum + p.price } * Correct and clarify Array#to_sentence docs. #5458 [brad@madriska.com] diff --git a/activesupport/lib/active_support/core_ext/enumerable.rb b/activesupport/lib/active_support/core_ext/enumerable.rb index 0d7d0159f9..92304a23f6 100644 --- a/activesupport/lib/active_support/core_ext/enumerable.rb +++ b/activesupport/lib/active_support/core_ext/enumerable.rb @@ -26,11 +26,18 @@ module Enumerable #:nodoc: # payments.sum { |p| p.price * p.tax_rate } # payments.sum(&:price) # - # This is instead of payments.inject(0) { |sum, p| sum + p.price } - def sum - inject(0) { |sum, element| sum + yield(element) } + # This is instead of payments.inject { |sum, p| sum + p.price } + # + # Also calculates sums without the use of a block: + # [5, 15, 10].sum # => 30 + def sum(&block) + if block_given? + map(&block).sum + else + inject { |sum, element| sum + element } + end end - + # Convert an enumerable to a hash. Examples: # # people.index_by(&:login) @@ -45,4 +52,4 @@ module Enumerable #:nodoc: end end -end
\ No newline at end of file +end diff --git a/activesupport/test/core_ext/enumerable_test.rb b/activesupport/test/core_ext/enumerable_test.rb index dada058d56..3d116e8d93 100644 --- a/activesupport/test/core_ext/enumerable_test.rb +++ b/activesupport/test/core_ext/enumerable_test.rb @@ -3,6 +3,9 @@ require File.dirname(__FILE__) + '/../../lib/active_support/core_ext/symbol' require File.dirname(__FILE__) + '/../../lib/active_support/core_ext/enumerable' Payment = Struct.new(:price) +class SummablePayment < Payment + def +(p) self.class.new(price + p.price) end +end class EnumerableTests < Test::Unit::TestCase def test_group_by @@ -19,13 +22,31 @@ class EnumerableTests < Test::Unit::TestCase assert group.all? {|person| person.name == name} end end - + def test_sums + assert_equal 30, [5, 15, 10].sum + assert_equal 30, [5, 15, 10].sum { |i| i } + + assert_equal 'abc', %w(a b c).sum + assert_equal 'abc', %w(a b c).sum { |i| i } + payments = [ Payment.new(5), Payment.new(15), Payment.new(10) ] assert_equal 30, payments.sum(&:price) assert_equal 60, payments.sum { |p| p.price * 2 } + + payments = [ SummablePayment.new(5), SummablePayment.new(15) ] + assert_equal SummablePayment.new(20), payments.sum + assert_equal SummablePayment.new(20), payments.sum { |p| p } end - + + def test_nil_sums + assert_raise(TypeError) { [5, 15, nil].sum } + + payments = [ Payment.new(5), Payment.new(15), Payment.new(10), Payment.new(nil) ] + assert_raise(TypeError) { payments.sum(&:price) } + assert_equal 60, payments.sum { |p| p.price.to_i * 2 } + end + def test_index_by payments = [ Payment.new(5), Payment.new(15), Payment.new(10) ] assert_equal( @@ -33,5 +54,4 @@ class EnumerableTests < Test::Unit::TestCase payments.index_by(&:price) ) end - end |