如何在Ruby中不覆盖重复键的情况下合并两个哈希?
问题描述：
是否有一种简单或优雅的方式来合并两个散列而不覆盖重复键?
Is there an easy or elegant way to merge two hashes without overwriting duplicate keys?
也就是说，如果键存在于原始散列中，我不想更改其值.
That is, if the key is present in the original hash I don't want to change its value.
答
如果你有两个散列，options 和 defaults，并且你想合并 defaults 到 options 而不覆盖现有的键，你真正想要做的是相反的:将 options 合并到 defaults 中:
If you have two hashes, options and defaults, and you want to merge defaults into options without overwriting existing keys, what you really want to do is the reverse: merge options into defaults:
options = defaults.merge(options)
或者，如果您使用 Rails，您可以这样做:
Or, if you're using Rails you can do:
options.reverse_merge!(defaults)