在perl中过滤哈希散列 [英] Filtering a hash of hash in perl

问题描述

我有一个哈希散列，我需要过滤。我确实发现了如何做查找，但没有回答我的问题。

I have a hash of hash that I need to filter. I did find how to do a lookup but it did not answer my question.

假设我有这样的哈希散列：

Say I have a hash of hash like that :

my %HoH = (
    flintstones => {
        husband   => "fred",
        pal       => "barney",
        town      => "springfield"
    },
    jetsons => {
        husband   => "george",
        wife      => "jane",
        "his boy" => "elroy",
    },
    simpsons => {
        husband   => "homer",
        wife      => "marge",
        kid       => "bart",
        town      => "springfield",
    },
);

我可以说我想要来自Springfield的所有城镇。

I lets say I want all the townfolks from springfield. I want the same hash of hash in output without the outsiders.

my %HoH = (
    flintstones => {
        husband   => "fred",
        pal       => "barney",
        town      => "springfield"
    },
    simpsons => {
        husband   => "homer",
        wife      => "marge",
        kid       => "bart",
        town      => "springfield",
    },
);

这似乎很愚蠢，但无法弄清楚如何过滤结构。我们的目标是在筛选后迭代Springfield的所有人。

It seems silly but can't figure out how to filter the struture. The goal would be to iterate on all the people of springfield after filtering.

我当然做了一些研究，最接近的是哈希切片。
但它们看起来很可怕。

I of course did some research and the closest thing I came by is hash slices. But they seem scary.

推荐答案

首先需要找到要移除的元素的键： / p>

You first need to find the keys of the elements you want to remove:

grep { $HoH{$_}{town} eq 'springfield' } keys(%HoH)

然后删除它们：

Then you delete them:

delete $HoH{$_} for grep { $HoH{$_}{town} eq 'springfield' } keys(%HoH);

或者使用散列片：

Or using a hash slice:

delete @HoH{ grep { $HoH{$_}{town} eq 'springfield' } keys(%HoH) };

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