11、正则表达式：匹配、锚定与修饰的全面指南

正则表达式：匹配、锚定与修饰的全面指南

1. 正则表达式基础

1.1 重复次数限制

{n,m} 表示匹配必须至少出现 n 次且不能超过 m 次。示例代码如下：

my $one_to_three_a = qr/ca{1,3}t/;
like(
    'cat',
    $one_to_three_a, "'cat' matches /ca{1,3}t/"
);
like(
    'caat',
    $one_to_three_a, "'caat' matches /ca{1,3}t/"
);
like(
    'caaat',
    $one_to_three_a, "'caaat' matches /ca{1,3}t/"
);
unlike( 'caaaat', $one_to_three_a, "'caaaat' does not match /ca{1,3}t/" );

1.2 贪婪与非贪婪匹配

1.2.1 贪婪匹配

+ 和 * 本身是贪婪量词，它们会尽可能多地匹配输入字符串。例如：

my $hot_meal = qr/hot.*meal/;
say 'Found a hot meal!' if 'I have a hot meal' =~ $hot_meal;
say 'Found a ho