在阵列pserved为了$ P $路口时做？ [英] Is order preserved in arrays when intersection is done?

问题描述

当我做两个数组的交集，有没有保证所得到的顺序是根据第一个数组的顺序？

When I do an intersection of two arrays, is there any guarantee that the resulting order is based on the order of the first array?

例如，如果我有

a = [1,2,3]
b = [3,2,1]

能 A和b 收益 [3,2,1] ，而不是 [1,2,3] （这是我所期望的）？

could a & b return [3,2,1], instead of [1,2,3] (which is what I'd expect)?

我找不到任何在任的RDoc的直接解决这一或Array镐头的文档。

I can't find anything directly addressing this in either RDoc's or the Pickaxe's documentation of Array.

RubySpec具有它一个规范创建以与阵列为了元素第一次遇到，但我应该承担YARV的Ruby将履行该规范？

RubySpec has a specification that it creates an array with elements in order they are first encountered, but should I assume YARV Ruby will honour that specification?

推荐答案

看起来是有保障的功能。他们在升级修订39415 上的RDoc描述。它在将来应该体现出来。

Looks like it is a guaranteed feature. They upgraded the RDoc description in revision 39415. It should be reflected sometime.

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