括号文本捕获 (Perl RegEx)

Question

我回来跟进this question。 假设我有文字

====Example 1====
Some text that I want to get that
may include line breaks
or special ~!@#$%^&*() characters

====Example 2====
Some more text that I don't want to get.

并使用$output = ($text =~ ====Example 1====\s*(.*?)\s*====); 尝试获取从“====Example 1====”到“Example 2”之前的四个等号的所有内容。

根据我所看到的on this site、regexpal.com 并通过自己运行它，Perl 找到并匹配文本，但 $output 仍然为空或被分配为“1”。我很确定我在捕获括号上做错了什么，但我不知道是什么。任何帮助，将不胜感激。 我的完整代码是：

$text = "====Example 1====\n
Some text that I want to get this text\n
may include line breaks\n
or special ~!@#$%^&*() characters\n
\n
====Example 2====]\n
Some more filler text that I don't want to get.";
my ($output) = $text =~ /====Example 1====\s*(.*?)\s*====/;
die "un-defined" unless defined $output;
print $output;

Answer 1

尝试使用括号强制列表上下文，并在匹配时使用/s，以便.也可以匹配换行符，

my ($output) = $text =~ / /s;

Answer 2

两件事。

1. 将 /s 标志应用于正则表达式，让它知道正则表达式的输入可能是多行。
2. 将括号改为$output，而不是($text ~= regex);。

例子：

($output) = $text =~ /====Example\s1====\s*(.*?)\s*====/s;

例如，将其放入如下脚本中：

#!/usr/bin/env perl

$text="
====Example 1====
Some text that I want to get that
may include line breaks
or special ~!@#$%^&*() characters

====Example 2====
Some more text that I don't want to get.
";

print "full text:","\n";
&hr;
print "$text","\n";
&hr;

($output) = $text =~ /====Example\s1====\s*(.*?)\s*====/s;
print "desired output of regex:","\n";
&hr;
print "$output","\n";
&hr;

sub hr {
        print "-" x 80, "\n";
}

让你输出如下：

bash$ perl test.pl
--------------------------------------------------------------------------------
full text:
--------------------------------------------------------------------------------

====Example 1====
Some text that I want to get that
may include line breaks
or special ~!@#0^&*() characters

====Example 2====
Some more text that I don't want to get.

--------------------------------------------------------------------------------
desired output of regex:
--------------------------------------------------------------------------------
Some text that I want to get that
may include line breaks
or special ~!@#0^&*() characters
--------------------------------------------------------------------------------