在Ruby中，如何设置嵌套散列的默认值？ [英] In Ruby, how to set a default value for a nested hash?

问题描述

最近我找到了一种在Ruby中正确创建和使用嵌套散列的方法。我立即找到了Paul Morie的解决方案，他回答了他自己的问题：

hash = Hash.new {| h，k | h [k] = {}}


我很快就使用了这个功能，很高兴报告它的工作原理。但是，正如标题所说，我希望次要，内部哈希默认为返回0 。

。

我知道你可以在其构造函数中定义散列的默认返回值（ Hash.new（0））或者使用 .default （ hash.default（0））。

但是，你会如何在散列内部使用散列来实现这一点？解析方案

显然我只需要做：

>

hash = Hash.new {| h，k | h [k] = Hash.new（0）}

哎呀。我会尽量不要急于在下次提问。

I recently looked for a way to correctly create and use nested hashes in Ruby. I promptly found a solution by Paul Morie, who answered his own question: hash = Hash.new { |h,k| h[k] = {} }

I promptly went to use this and am glad to report it works. However, as the title says, I'd like the "secondary", "inside" hashes to return 0 by default.

I'm aware that you can define the default return value of a hash both in its constructor ("Hash.new(0)") or using .default ("hash.default(0)").

But how would you do this with hashes inside a hash?

解决方案

Apparently I only had to do:

hash = Hash.new { |h,k| h[k] = Hash.new(0) }

Whoops. I'll try not to be so hasty to ask a question next time.

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