Ruby中数组或散列元素的别名

数组示例

arr = ["a", "b", "c"]
# TODO create an alias for arr[1] as x
x = "X"
# arr should  be ["a", "X", "c"] here

hash = { :a => "aaa", :b => "bbb" , :c => "ccc" }
# TODO create an alias for hash[:b] as y
y = "YYY"
# hash should be { :a => "aaa", :b => "YYY" , :c => "ccc" } here

以及变量的别名?

var = 5
# TODO create an alias for var as z
z = 7
# var should be 7 here

隐喻:我想从一个更大的数据结构中选择上下文,我想用一个简短的名字访问它。

更新

irb(main):001:0> arr = [ { "a" => 1, "b" => 2}, { "x" => 7, "y" => 8 } ]
=> [{"a"=>1, "b"=>2}, {"x"=>7, "y"=>8}]
irb(main):002:0> i = arr[0]
=> {"a"=>1, "b"=>2}
irb(main):004:0> j = arr[1]
=> {"x"=>7, "y"=>8}
irb(main):007:0> j["z"] = 9
=> 9
irb(main):008:0> j
=> {"x"=>7, "y"=>8, "z"=>9}
irb(main):009:0> arr
=> [{"a"=>1, "b"=>2}, {"x"=>7, "y"=>8, "z"=>9}]