diff options
| -rw-r--r-- | activerecord/lib/active_record/associations/has_many_through_association.rb | 26 |
1 files changed, 9 insertions, 17 deletions
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb index 8a8149b777..2322a49931 100644 --- a/activerecord/lib/active_record/associations/has_many_through_association.rb +++ b/activerecord/lib/active_record/associations/has_many_through_association.rb @@ -164,32 +164,24 @@ module ActiveRecord end def difference(a, b) - set_a = as_set(a) - set_b = as_set(b) + distribution = distribution(b) - from_set(set_a - set_b) + a.reject { |record| mark_occurrence(distribution, record) } end def intersection(a, b) - set_a = as_set(a) - set_b = as_set(b) + distribution = distribution(b) - from_set(set_a & set_b) + a.select { |record| mark_occurrence(distribution, record) } end - def as_set(records) - records.zip(occurences(records)) + def mark_occurrence(distribution, record) + distribution[record] > 0 && distribution[record] -= 1 end - def from_set(record_set) - record_set.map(&:first) - end - - def occurences(array) - counts = Hash.new(0) - - array.map do |object| - counts[object] += 1 + def distribution(array) + array.each_with_object(Hash.new(0)) do |record, distribution| + distribution[record] += 1 end end |