正則表達式多行匹配，不包括包含字符串的行

Question

在以下正則表達式中：

EXCLUDE this entire line
include this line
and this as single match
and EXCLUDE this line

我想返回一個包含兩行的匹配：

include this line
and this as single match

我想使用EXCLUDE作為字符串，標識不應包含整行。

編輯：如果我可以將第一個匹配項與“EXCLUDE”（或文檔末尾以先發生者為准）匹配，那也可以

Answer 1

您可以在正則表達式的匹配項上拆分字符串

^.*\bEXCLUDE\b.*\R

設置了全局和多行標志。

例如，在 Ruby 中，如果變量str保存了字符串

Firstly include this line
EXCLUDE this entire line
include this line
and this as single match
and EXCLUDE this line
Lastly include this line

那么String#split方法可用於生成包含三個字符串的數組。

str.split(/^.*\bEXCLUDE\b.*\R/)
  #=> ["Firstly include this line",
  #    "include this line\nand this as single match",
  #    "Lastly include this line"]

許多語言都有與 Ruby 的split相當的方法或函數。

演示

正則表達式可以分解如下。

^        # match the beginning of a line
.*       # match zero or more characters other than line
         # terminators, as many as possible
\b       # match word boundary
EXCLUDE  # match literal
\b       # match word boundary
.*       # match zero or more characters other than line
         # terminators, as many as possible
\R       # match line terminator
 

Answer 2

使用 pcre 您可以使用\K來獲取到目前為止匹配的內容，並首先匹配包含排除的行：

^.*\bEXCLUDE\b.*\K(?:\R(?!.*\bEXCLUDE\b).*)+

正則表達式演示

如果要匹配所有不包含排除的行，則使用連續行：

(?:(?:^|\R)(?!.*\bEXCLUDE\b).*)+

正則表達式演示

或使用跳過失敗方法：

^.*\bEXCLUDE\b.*\R(*SKIP)(*F)|.+(?:\R(?!.*\bEXCLUDE\b).*)*

正則表達式演示

Answer 3

您還可以將這些行與EXCLUDE匹配，並使用它將您的文本拆分為您要查找的塊：

<?php

$input = 'First include this line
EXCLUDE this entire line
include this line
and this as single match
and EXCLUDE this line
Lastly include this line';

// ^ matches the beginning of a line.
// .* matches anything (except new lines) zero or multiple times.
// \b matches a word boundary (to avoid matching NOEXCLUDE).
// $ matches the end of a line.
$pattern = '/^.*\bEXCLUDE\b.*$/m';

// Split the text with all lines containing the EXCLUDE word.
$desired_blocks = preg_split($pattern, $input);

// Get rid of the new lines around the matched blocks.
array_walk(
    $desired_blocks,
    function (&$block) {
        // \R matches any Unicode newline sequence.
        // ^ matches the beginning of the string.
        // $ matches the end of the string.
        // | = or
        $block = preg_replace('/^\R+|\R+$/', '', $block);
    }
);

var_export($desired_blocks);

在這里演示： https ://onlinephp.io/c/4216a

輸出：

array (
  0 => 'First include this line',
  1 => 'include this line
and this as single match',
  2 => 'Lastly include this line',
)