按值然后按键对散列进行排序(但键是相反的) [英] Sorting a hash by value then by key (but the key is reversed)

问题描述

标题说明了一切.

total = {"Bob"=>37, "Alice"=>42, "Carl"=>42}

我想先按值排序，然后再按键排序，但键要按降序排列.

I want to sort it by value, and then by key, but with the key in descending order.

像这样:

{"Bob"=>37, "Carl"=>42, "Alice"=>42}

我尝试过:

return total.sort_by { |k, v| [v, k] }

但是从这里我不知道如何反转k ...

But from here I don't know how to reverse k...

推荐答案

使用排序:

total = {"Bob"=>37, "Alice"=>42, "Carl"=>42}
total.sort { |(k1, v1), (k2, v2)| [v1, k2] <=> [v2, k1] }.to_h
# => {"Bob"=>37, "Carl"=>42, "Alice"=>42}

首先，按值(v1 <=> v2)排序，然后按键(k2 <=> k1)反向排序，由于我们同时需要它，因此将其放入数组中.

First, sort by values (v1 <=> v2) and then reverse sort by keys (k2 <=> k1), and since we need it simultaneously, put it into array.

@ Mirror318，它看起来很吓人，在这里查看出色的解释:

@Mirror318, it just looks scary, take a look at the excellent explanation here: What is the Ruby <=> (spaceship) operator?

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