Document Hash#extract!.

2 files changed, 14 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 d7fb2da0fb..0484d8e5d8 100644
--- a/activesupport/lib/active_support/core_ext/hash/slice.rb
+++ b/activesupport/lib/active_support/core_ext/hash/slice.rb
@@ -30,6 +30,8 @@ class Hash
     omit
   end
 
+  # Removes and returns the key/value pairs matching the given keys.
+  #   {:a => 1, :b => 2, :c => 3, :d => 4}.extract!(:a, :b) # => {:a => 1, :b => 2}
   def extract!(*keys)
     result = {}
     keys.each {|key| result[key] = delete(key) }
diff --git a/railties/guides/source/active_support_core_extensions.textile b/railties/guides/source/active_support_core_extensions.textile
index 781d3d08cd..a672b17e4a 100644
--- a/railties/guides/source/active_support_core_extensions.textile
+++ b/railties/guides/source/active_support_core_extensions.textile
@@ -2696,6 +2696,18 @@ hash                   # => {:a => 1}
 
 NOTE: Defined in +active_support/core_ext/hash/slice.rb+.
 
+h4. Extracting
+
+The method +extract!+ removes and returns the key/value pairs matching the given keys.
+
+<ruby>
+hash = {:a => 1, :b => 2}
+rest = hash.extract!(:a) # => {:a => 1}
+hash                     # => {:b => 2}
+</ruby>
+
+NOTE: Defined in +active_support/core_ext/hash/slice.rb+.
+
 h4. Indifferent Access
 
 The method +with_indifferent_access+ returns an +ActiveSupport::HashWithIndifferentAccess+ out of its receiver: