Hash#deep_*_keys(!) recurse into nested arrays.

Following methods now recursively transform nested arrays, too.

* Hash#deep_transform_keys
* Hash#deep_transform_keys!
* Hash#deep_stringify_keys
* Hash#deep_stringify_keys!
* Hash#deep_symbolize_keys
* Hash#deep_symbolize_keys!

activesupport/CHANGELOG.md

+*   `Hash#deep_transform_keys` and `Hash#deep_transform_keys!` now transform hashes
+    in nested arrays.  This change also applies to `Hash#deep_stringify_keys`,
+    `Hash#deep_stringify_keys!`, `Hash#deep_symbolize_keys` and
+    `Hash#deep_symbolize_keys!`.
+
+    *OZAWA Sakuro*
+
 *   Override `Time.at` to support the passing of Time-like values when called with a single argument.
 
     *Andrew White*

activesupport/lib/active_support/core_ext/hash/keys.rb

@@ -73,34 +73,26 @@ def assert_valid_keys(*valid_keys)
 
   # Return a new hash with all keys converted by the block operation.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   #
   #  hash = { person: { name: 'Rob', age: '28' } }
   #
   #  hash.deep_transform_keys{ |key| key.to_s.upcase }
   #  # => { "PERSON" => { "NAME" => "Rob", "AGE" => "28" } }
   def deep_transform_keys(&block)
-    result = {}
-    each do |key, value|
-      result[yield(key)] = value.is_a?(Hash) ? value.deep_transform_keys(&block) : value
-    end
-    result
+    _deep_transform_keys_in_object(self, &block)
   end
 
   # Destructively convert all keys by using the block operation.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   def deep_transform_keys!(&block)
-    keys.each do |key|
-      value = delete(key)
-      self[yield(key)] = value.is_a?(Hash) ? value.deep_transform_keys!(&block) : value
-    end
-    self
+    _deep_transform_keys_in_object!(self, &block)
   end
 
   # Return a new hash with all keys converted to strings.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   #
   #   hash = { person: { name: 'Rob', age: '28' } }
   #
@@ -112,14 +104,14 @@ def deep_stringify_keys
 
   # Destructively convert all keys to strings.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   def deep_stringify_keys!
     deep_transform_keys!{ |key| key.to_s }
   end
 
   # Return a new hash with all keys converted to symbols, as long as
   # they respond to +to_sym+. This includes the keys from the root hash
-  # and from all nested hashes.
+  # and from all nested hashes and arrays.
   #
   #   hash = { 'person' => { 'name' => 'Rob', 'age' => '28' } }
   #
@@ -131,8 +123,38 @@ def deep_symbolize_keys
 
   # Destructively convert all keys to symbols, as long as they respond
   # to +to_sym+. This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   def deep_symbolize_keys!
     deep_transform_keys!{ |key| key.to_sym rescue key }
   end
+
+  private
+    # support methods for deep transforming nested hashes and arrays
+    def _deep_transform_keys_in_object(object, &block)
+      case object
+      when Hash
+        object.each_with_object({}) do |(key, value), result|
+          result[yield(key)] = _deep_transform_keys_in_object(value, &block)
+        end
+      when Array
+        object.map {|e| _deep_transform_keys_in_object(e, &block) }
+      else
+        object
+      end
+    end
+
+    def _deep_transform_keys_in_object!(object, &block)
+      case object
+      when Hash
+        object.keys.each do |key|
+          value = object.delete(key)
+          object[yield(key)] = _deep_transform_keys_in_object!(value, &block)
+        end
+        object
+      when Array
+        object.map! {|e| _deep_transform_keys_in_object!(e, &block)}
+      else
+        object
+      end
+    end
 end

activesupport/test/core_ext/hash_ext_test.rb

@@ -36,6 +36,10 @@ def setup
     @nested_illegal_symbols = { [] => { [] => 3} }
     @upcase_strings = { 'A' => 1, 'B' => 2 }
     @nested_upcase_strings = { 'A' => { 'B' => { 'C' => 3 } } }
+    @string_array_of_hashes = { 'a' => [ { 'b' => 2 }, { 'c' => 3 }, 4 ] }
+    @symbol_array_of_hashes = { :a => [ { :b => 2 }, { :c => 3 }, 4 ] }
+    @mixed_array_of_hashes = { :a => [ { :b => 2 }, { 'c' => 3 }, 4 ] }
+    @upcase_array_of_hashes = { 'A' => [ { 'B' => 2 }, { 'C' => 3 }, 4 ] }
   end
 
   def test_methods
@@ -72,6 +76,9 @@ def test_deep_transform_keys
     assert_equal @nested_upcase_strings, @nested_symbols.deep_transform_keys{ |key| key.to_s.upcase }
     assert_equal @nested_upcase_strings, @nested_strings.deep_transform_keys{ |key| key.to_s.upcase }
     assert_equal @nested_upcase_strings, @nested_mixed.deep_transform_keys{ |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @string_array_of_hashes.deep_transform_keys{ |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @symbol_array_of_hashes.deep_transform_keys{ |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @mixed_array_of_hashes.deep_transform_keys{ |key| key.to_s.upcase }
   end
 
   def test_deep_transform_keys_not_mutates
@@ -97,6 +104,9 @@ def test_deep_transform_keys!
     assert_equal @nested_upcase_strings, @nested_symbols.deep_dup.deep_transform_keys!{ |key| key.to_s.upcase }
     assert_equal @nested_upcase_strings, @nested_strings.deep_dup.deep_transform_keys!{ |key| key.to_s.upcase }
     assert_equal @nested_upcase_strings, @nested_mixed.deep_dup.deep_transform_keys!{ |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @string_array_of_hashes.deep_dup.deep_transform_keys!{ |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @symbol_array_of_hashes.deep_dup.deep_transform_keys!{ |key| key.to_s.upcase }
+    assert_equal @upcase_array_of_hashes, @mixed_array_of_hashes.deep_dup.deep_transform_keys!{ |key| key.to_s.upcase }
   end
 
   def test_deep_transform_keys_with_bang_mutates
@@ -122,6 +132,9 @@ def test_deep_symbolize_keys
     assert_equal @nested_symbols, @nested_symbols.deep_symbolize_keys
     assert_equal @nested_symbols, @nested_strings.deep_symbolize_keys
     assert_equal @nested_symbols, @nested_mixed.deep_symbolize_keys
+    assert_equal @symbol_array_of_hashes, @string_array_of_hashes.deep_symbolize_keys
+    assert_equal @symbol_array_of_hashes, @symbol_array_of_hashes.deep_symbolize_keys
+    assert_equal @symbol_array_of_hashes, @mixed_array_of_hashes.deep_symbolize_keys
   end
 
   def test_deep_symbolize_keys_not_mutates
@@ -147,6 +160,9 @@ def test_deep_symbolize_keys!
     assert_equal @nested_symbols, @nested_symbols.deep_dup.deep_symbolize_keys!
     assert_equal @nested_symbols, @nested_strings.deep_dup.deep_symbolize_keys!
     assert_equal @nested_symbols, @nested_mixed.deep_dup.deep_symbolize_keys!
+    assert_equal @symbol_array_of_hashes, @string_array_of_hashes.deep_dup.deep_symbolize_keys!
+    assert_equal @symbol_array_of_hashes, @symbol_array_of_hashes.deep_dup.deep_symbolize_keys!
+    assert_equal @symbol_array_of_hashes, @mixed_array_of_hashes.deep_dup.deep_symbolize_keys!
   end
 
   def test_deep_symbolize_keys_with_bang_mutates
@@ -192,6 +208,9 @@ def test_deep_stringify_keys
     assert_equal @nested_strings, @nested_symbols.deep_stringify_keys
     assert_equal @nested_strings, @nested_strings.deep_stringify_keys
     assert_equal @nested_strings, @nested_mixed.deep_stringify_keys
+    assert_equal @string_array_of_hashes, @string_array_of_hashes.deep_stringify_keys
+    assert_equal @string_array_of_hashes, @symbol_array_of_hashes.deep_stringify_keys
+    assert_equal @string_array_of_hashes, @mixed_array_of_hashes.deep_stringify_keys
   end
 
   def test_deep_stringify_keys_not_mutates
@@ -217,6 +236,9 @@ def test_deep_stringify_keys!
     assert_equal @nested_strings, @nested_symbols.deep_dup.deep_stringify_keys!
     assert_equal @nested_strings, @nested_strings.deep_dup.deep_stringify_keys!
     assert_equal @nested_strings, @nested_mixed.deep_dup.deep_stringify_keys!
+    assert_equal @string_array_of_hashes, @string_array_of_hashes.deep_dup.deep_stringify_keys!
+    assert_equal @string_array_of_hashes, @symbol_array_of_hashes.deep_dup.deep_stringify_keys!
+    assert_equal @string_array_of_hashes, @mixed_array_of_hashes.deep_dup.deep_stringify_keys!
   end
 
   def test_deep_stringify_keys_with_bang_mutates