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Added Hash#except which is the inverse of Hash#slice -- return the ha…

…sh except the keys that are specified [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7172 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
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1 parent 5b2be62 commit cb2381696029ad839ecddad08afea061d07685fb @dhh dhh committed Jul 9, 2007
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2 activesupport/CHANGELOG
@@ -1,5 +1,7 @@
*SVN*
+* Added Hash#except which is the inverse of Hash#slice -- return the hash except the keys that are specified [DHH]
+
* Added support for pluralization with a different starting letter than the singular version (cow/kine) #4929 [norri_b/hasmanyjosh]
* Demote Hash#to_xml to use XmlSimple#xml_in_string so it can't read files or stdin. #8453 [candlerb, Jeremy Kemper]
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3 activesupport/lib/active_support/core_ext/hash.rb
@@ -1,4 +1,4 @@
-%w(keys indifferent_access reverse_merge conversions diff slice).each do |ext|
+%w(keys indifferent_access reverse_merge conversions diff slice except).each do |ext|
require "#{File.dirname(__FILE__)}/hash/#{ext}"
end
@@ -9,4 +9,5 @@ class Hash #:nodoc:
include ActiveSupport::CoreExtensions::Hash::Conversions
include ActiveSupport::CoreExtensions::Hash::Diff
include ActiveSupport::CoreExtensions::Hash::Slice
+ include ActiveSupport::CoreExtensions::Hash::Except
end
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24 activesupport/lib/active_support/core_ext/hash/except.rb
@@ -0,0 +1,24 @@
+require 'set'
+
+module ActiveSupport #:nodoc:
+ module CoreExtensions #:nodoc:
+ module Hash #:nodoc:
+ # Return a hash that includes everything but the given keys. This is useful for
+ # limiting a set of parameters to everything but a few known toggles:
+ #
+ # @person.update_attributes(params[:person].except(:admin))
+ module Except
+ # Returns a new hash without the given keys.
+ def except(*keys)
+ rejected = Set.new(respond_to?(:convert_key) ? keys.map { |key| convert_key(key) } : keys)
+ reject { |key,| rejected.include?(key) }
+ end
+
+ # Replaces the hash without only the given keys.
+ def except!(*keys)
+ replace(except(*keys))
+ end
+ end
+ end
+ end
+end
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13 activesupport/test/core_ext/hash_ext_test.rb
@@ -277,6 +277,19 @@ def test_indifferent_slice
assert_equal expected, copy
end
end
+
+ def test_except
+ original = { :a => 'x', :b => 'y', :c => 10 }
+ expected = { :a => 'x', :b => 'y' }
+
+ # Should return a new hash with only the given keys.
+ assert_equal expected, original.except(:c)
+ assert_not_equal expected, original
+
+ # Should replace the hash with only the given keys.
+ assert_equal expected, original.except!(:c)
+ assert_equal expected, original
+ end
end
class IWriteMyOwnXML

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