Regex 条件正则表达式捕获，来自哈希的grepping数组

给定以下匿名哈希数组：

$fields_dump = [
    {
        'DEFAULT_FIELD_LABEL' => 'telco_hier_building',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'building',
    },
    {
        'DEFAULT_FIELD_LABEL' => 'Request Type',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'request_type',

    },
    {
        'DEFAULT_FIELD_LABEL' => 'Request Completion Date',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'request_completion_date',
    },

我想通过

DEFAULT\u FIELD\u LABEL

有条件地为

telco\u hier\u building

或

telco\u imac\u building

的值对数组进行grep。当它成功时，我需要提取匹配值的第二个下划线

我正在使用以下代码：

if  ( grep { $_->{DEFAULT_FIELD_LABEL} =~ m/(telco_hier_|telco_imac_)building/ } @$fields_dump ) {
    my $telco_prefix = $1;
    ...
}

条件触发正确，但regex

$1

赋值为空，在本例中，它应该是

telco\u hier\u

---

我做错了什么？

匹配的范围是

{}

代码块。您可以使用

来代替

循环：

use warnings;
use strict;

my $fields_dump = [
    {
        'DEFAULT_FIELD_LABEL' => 'telco_hier_building',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'building',
    },
    {
        'DEFAULT_FIELD_LABEL' => 'Request Type',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'request_type',

    },
    {
        'DEFAULT_FIELD_LABEL' => 'Request Completion Date',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'request_completion_date',
    },
];

for (@{ $fields_dump }) {
    if ($_->{DEFAULT_FIELD_LABEL} =~ m/(telco_hier_|telco_imac_)building/) {
        my $telco_prefix = $1;
        print "$telco_prefix\n";
    }
}

输出为：

telco_hier_

---

进一步解释参见。

匹配的范围是

{}

代码块。您可以改用

for

循环：

use warnings;
use strict;

my $fields_dump = [
    {
        'DEFAULT_FIELD_LABEL' => 'telco_hier_building',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'building',
    },
    {
        'DEFAULT_FIELD_LABEL' => 'Request Type',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'request_type',

    },
    {
        'DEFAULT_FIELD_LABEL' => 'Request Completion Date',
        'APPROVER_ORDER' => '0',
        'IS_READONLY' => '0',
        'FORM_ID' => '3913',
        'REFERENCE' => 'request_completion_date',
    },
];

for (@{ $fields_dump }) {
    if ($_->{DEFAULT_FIELD_LABEL} =~ m/(telco_hier_|telco_imac_)building/) {
        my $telco_prefix = $1;
        print "$telco_prefix\n";
    }
}

输出为：

telco_hier_

进一步解释请参见