Ruby 哈希白名单过滤器 [英] Ruby Hash Whitelist Filter

问题描述

我试图弄清楚如何将键和值对从一个过滤器过滤到另一个过滤器中

I am trying to figure out how I can filter out key and value pairs from one filter into another

例如我想取这个哈希

x = { "one" => "one", "two" => "two", "three" => "three"}

y = x.some_function

y == { "one" => "one", "two" => "two"}

感谢您的帮助

可能应该提到，在这个例子中，我希望它充当白名单过滤器.也就是说，我知道我想要什么，而不是我不想要什么.

should probably mention that in this example, I want it to behave as a whitelist filter. That is, I know what I want, not what I don't want.

推荐答案

也许这就是你想要的.

wanted_keys = %w[one two]
x = { "one" => "one", "two" => "two", "three" => "three"}
x.select { |key,_| wanted_keys.include? key }

包含在例如 Enumerable mixin 中.Array 和 Hash 提供了很多有用的方法，例如 select/reject/each/etc.. 我建议您使用 ri Enumerable 查看它的文档.

The Enumerable mixin which is included in e.g. Array and Hash provides a lot of useful methods like select/reject/each/etc.. I suggest that you take a look at the documentation for it with ri Enumerable.

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