如何在没有新键的情况下合并两个哈希 [英] How to merge two hashes with no new keys

问题描述

如何合并两个没有新键的哈希，这意味着合并将合并两个哈希中都存在的键?

How could I merge two hashes that results in no new keys, meaning the merge would merge keys that exist in both hashes?

例如，我想要以下内容:

For example, I want the following:

h = {:foo => "bar"}
j = {:foo => "baz", :extra => "value"}

puts h.merge(j)    # {:foo => "baz"}

我正在寻找一种非常干净的方式来执行此操作，因为我当前的实现非常混乱.

I'm looking for a really clean way of doing this as my current implementation is pretty messy.

推荐答案

您可以从第二个哈希中删除不在第一个哈希中的键，然后合并:

You could remove keys that weren't in the first hash from the second hash, then merge:

h.merge j.select { |k| h.keys.include? k }

与我编辑的替代方案不同，如果您决定将其更改为 merge! 或 update，这是安全的.

Unlike my edited-out alternative, this is safe if you decide to change it to a merge! or update.

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