[{"@opt"=>"A", nil=>"1"}]
[{"@opt"=>"A", nil=>"1"}, {"@opt"=>"B", nil=>"2"}]
["1"]
["A"]
["1", "2"]
--
<member><uid opt="A">1</uid><name>name1</name><email>name1@com</email></member><member><uid opt="B">2</uid><name>name2</name><email>name2@com</email></member><member><uid>3</uid><name>name3</name><email>name3@com</email></member><member><uid>4</uid><name>name4</name><email>name4@com</email></member>
--
<name>name1</name><uid opt="A">1</uid><email>name1@com</email>
<name>name2</name><uid opt="B">2</uid><email>name2@com</email>
<name>name3</name><uid>3</uid><email>name3@com</email>
<name>name4</name><uid>4</uid><email>name4@com</email>