如何匹配正則表達式中的多個（N）空格？

Question

我有一個正則表達式(?<={% start %}).*?(?={% end %})匹配兩個自定義標籤之間的所有內容。

的問題是，如果存在內部空間的標籤（例如， 「{％     開始％}」）和I添加\s+?條件，正則表達式失敗。下面的代碼不起作用：(?<={%\s+?start\s+?%}).*?(?={%\s+?end\s+?%})，我在PHP中得到一個錯誤：

preg_match_all(): Compilation failed: lookbehind assertion is not fixed length at offset 25 

同樣的正則表達式的作品，如果我刪除前瞻/回顧後：({%\s+?(start|end)\s+%})。

請指教。

Answer 1

說明

試試這個permlink

[{]%\s*?\b([^}]*start[^}]*)\b\s*?%[}]\s*?\b(.*?)\b\s*?[{]%\s*\b([^}]*end[^}]*)\b\s*%[}] 

這將匹配您的{%和%}括號內的所有文本，並把價值到他們組之前將自動修剪的文本。

集團0獲取整個匹配的字符串

1. 得到的開始標記文本
2. 得到內部文本
3. 獲取結束標記文本

免責聲明

這可能會有一些邊緣情況下，如果你有複雜的數據嵌套到子，正則表達式將失敗，如果是的話，那麼使用正則表達式可能不是這項任務的最佳工具。

摘要

[{]%\s*?\b([^}]*start[^}]*)\b\s*?%[}]\s*?\b(.*?)\b\s*?[{]%\s*\b([^}]*end[^}]*)\b\s*%[}] 
Char class [{] matches one of the following chars: { 
% Literal `%` 
\s 0 to infinite times [lazy] Whitespace [\t \r\n\f] 
\b Word boundary: match in between (^\w|\w$|\W\w|\w\W) 
1st Capturing group ([^}]*start[^}]*) 
Negated char class [^}] infinite to 0 times matches any char except: } 
start Literal `start` 
Negated char class [^}] infinite to 0 times matches any char except: } 
\b Word boundary: match in between (^\w|\w$|\W\w|\w\W) 
\s 0 to infinite times [lazy] Whitespace [\t \r\n\f] 
% Literal `%` 
Char class [}] matches one of the following chars: } 
\s 0 to infinite times [lazy] Whitespace [\t \r\n\f] 
\b Word boundary: match in between (^\w|\w$|\W\w|\w\W) 
2nd Capturing group (.*?) 
. 0 to infinite times [lazy] Any character (except newline) 
\b Word boundary: match in between (^\w|\w$|\W\w|\w\W) 
\s 0 to infinite times [lazy] Whitespace [\t \r\n\f] 
Char class [{] matches one of the following chars: { 
% Literal `%` 
\s infinite to 0 times Whitespace [\t \r\n\f] 
\b Word boundary: match in between (^\w|\w$|\W\w|\w\W) 
3rd Capturing group ([^}]*end[^}]*) 
Negated char class [^}] infinite to 0 times matches any char except: } 
end Literal `end` 
Negated char class [^}] infinite to 0 times matches any char except: } 
\b Word boundary: match in between (^\w|\w$|\W\w|\w\W) 
\s infinite to 0 times Whitespace [\t \r\n\f] 
% Literal `%` 
Char class [}] matches one of the following chars: } 

PHP例如

與示例文本 {% start %} this is a sample text 1 {% end %}{% start %} this is a sample text 2 {% end %}

<?php 
$sourcestring="your source string"; 
preg_match_all('/[{]%\s*?\b([^}]*start[^}]*)\b\s*?%[}]\s*?\b(.*?)\b\s*?[{]%\s*\b([^}]*end[^}]*)\b\s*%[}]/i',$sourcestring,$matches); 
echo "<pre>".print_r($matches,true); 
?> 

$matches Array: 
(
    [0] => Array 
     (
      [0] => {% start %} this is a sample text 1 {% end %} 
      [1] => {% start %} this is a sample text 2 {% end %} 
     ) 

    [1] => Array 
     (
      [0] => start 
      [1] => start 
     ) 

    [2] => Array 
     (
      [0] => this is a sample text 1 
      [1] => this is a sample text 2 
     ) 

    [3] => Array 
     (
      [0] => end 
      [1] => end 
     ) 

)