1 files changed, 16 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/hash/slice.rb b/activesupport/lib/active_support/core_ext/hash/slice.rb
index 6fe5e05330..c270e3906b 100644
--- a/activesupport/lib/active_support/core_ext/hash/slice.rb
+++ b/activesupport/lib/active_support/core_ext/hash/slice.rb
@@ -11,6 +11,11 @@ module ActiveSupport #:nodoc:
       #   end
       #
       #   search(options.slice(:mass, :velocity, :time))
+      #
+      # Also allows leaving out certain keys. This is useful when duplicating
+      # a hash but omitting a certain subset:
+      #
+      #   Event.new(event.attributes.without(:id, :user_id))
       module Slice
         # Returns a new hash with only the given keys.
         def slice(*keys)
@@ -22,6 +27,17 @@ module ActiveSupport #:nodoc:
         def slice!(*keys)
           replace(slice(*keys))
         end
+
+        # Returns a new hash without the given keys.
+        def without(*keys)
+          allowed = self.keys - (respond_to?(:convert_key) ? keys.map { |key| convert_key(key) } : keys)
+          slice(*allowed)
+        end
+
+        # Replaces the hash without the given keys.
+        def without!(*keys)
+          replace(without(*keys))
+        end
       end
     end
   end