Perl:将哈希键与正则表达式匹配 [英] Perl: Matching hash keys to a regular expression

问题描述

我想知道 Perl 是否有一种内置方法来检查哈希元素是否存在，其键与特定正则表达式匹配.例如:

I'm wondering if Perl has a built-in way to check for the existence of a hash element with a key matching a particular regex. For example:

my %h = ( 'twelve' => 12, 'thirteen' => 13, 'fourteen' => 14 );

我想知道是否有任何方法可以做到这一点:

I'm wondering if there is any way to do this:

print "We have 12
" if exists $h{twelve};
print "We have some teens
" if exists $h{/.*teen$/};

推荐答案

智能匹配运算符 执行此操作(自 Perl v5.10 起可用).

The smart match operator does this (available since Perl v5.10).

$a      $b        Type of Match Implied    Matching Code
======  =====     =====================    =============
...
Regex   Hash      hash key grep            grep /$a/, keys %$b
...

示例用法:

# print if any key in %h ends in "teen"
print "We have some teens
" if /.*teen$/ ~~ %h;

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