这是我无法理解的代码的简化版本:
1.9.3p448 :004 > a = {a: 1, b: 2}
=> {:a=>1, :b=>2}
1.9.3p448 :005 > b = a
=> {:a=>1, :b=>2}
1.9.3p448 :006 > b[:c] = 3
=> 3
1.9.3p448 :007 > a
=> {:a=>1, :b=>2, :c=>3}
1.9.3p448 :008 >
我不明白为什么a
会改变。只想改变b
并保持a
其原始价值。