added example for hash slice method [ci skip]

1 files changed, 8 insertions, 2 deletions

diff --git a/activesupport/lib/active_support/core_ext/hash/slice.rb b/activesupport/lib/active_support/core_ext/hash/slice.rb
index 8ad600b171..41b2279013 100644
--- a/activesupport/lib/active_support/core_ext/hash/slice.rb
+++ b/activesupport/lib/active_support/core_ext/hash/slice.rb
@@ -1,6 +1,12 @@
 class Hash
-  # Slice a hash to include only the given keys. This is useful for
-  # limiting an options hash to valid keys before passing to a method:
+  # Slice a hash to include only the given keys. Returns a hash containing 
+  # the given keys.
+  # 
+  #   { a: 1, b: 2, c: 3, d: 4 }.slice(:a, :b)
+  #   # => {:a=>1, :b=>2}
+  # 
+  # This is useful for limiting an options hash to valid keys before 
+  # passing to a method:
   #
   #   def search(criteria = {})
   #     criteria.assert_valid_keys(:mass, :velocity, :time)