密钥和散列值将具有相同的“顺序”在Perl中？ [英] Will keys and values of a hash have the same "order" in Perl?

问题描述

我知道一个散列不是在perl中排序的。我所关心的是如果我可以依靠与索引关系产生的键和值。

I understand that a hash is not ordered in perl. What I am concerned about is if I can depend on the keys and values coming out with an index relationship.

假设我有这个散列值

my %h = ("a" => 1, "b" => 2, "c" => 3, "d" => 4);

如果我做了键％h ，我可能会得到

If I do keys %h, I might get

("b", "a", "d", "c")

我会保证值％h 会以相同的顺序出现匹配键？我可以期待吗？

Would I be guaranteed that values %h would come out in the same order to match keys? Can I expect?

(2, 1, 4, 3)

还是不能保证键％h 和之间有任何索引关系。值％h ？

推荐答案

是的。只要散列没有改变（插入或删除），键，值和每一个将保持相同的顺序：

Yes. As long as the hash is not changed (insertion or deletion), keys, values and each will keep the same order:

只要给定的哈希值未经修改，您可以依赖键，值和每个重复返回相同的顺序。

So long as a given hash is unmodified you may rely on keys, values and each to repeatedly return the same order as each other.

- 从 perldoc -f keys

– from perldoc -f keys

所以你可以安全地复制一个哈希像：

So you could safely copy a hash like:

my %orig = ...;
my %copy;
@copy{keys %orig} = values %orig;

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