快速获取数组元素的索引红宝石 [英] Quickly get index of array element in Ruby

问题描述

由于我有一个巨大的数组，并从它的值。我想在数组中的价值指标。是否有任何其他方式，而再调用阵列＃指数来得到它？这个问题源于需要保持真正巨大的数组，并调用阵列＃指数的时间大量的。

Given I have a HUGE array, and a value from it. I want to get index of the value in array. Is there any other way, rather then call Array#index to get it? The problem comes from the need of keeping really huge array and calling Array#index enormous amount of times.

经过几次尝试，我发现的缓存的内部元素通过存储结构与（价值指数）字段，而不是本身的价值指标给出了性能的一大步（20X次夺冠）。

After a couple of tries I found that caching indexes inside elements by storing structs with (value, index) fields instead of the value itself gives a huge step in performance (20x times win).

不过我不知道是否有发现连接的元素的索引没有缓存（或有一个很好的缓存技术，这将提高了性能）更方便的方法。

Still I wonder if there's a more convenient way of finding index of en element without caching (or there's a good caching technique that will boost up the performance).

推荐答案

转换的数组哈希值。然后寻找的关键。

Convert the array into a hash. Then look for the key.

array = ['a', 'b', 'c']
hash = Hash[array.map.with_index.to_a]    # => {"a"=>0, "b"=>1, "c"=>2}
hash['b'] # => 1

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