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从字符串的开头和结尾删除
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分类: 技术问答 • 2022-03-11 15:58:45
问题描述：

How would I, given a string like this (for example), remove all break (<br>,<br />, and any other form) tags from only the beginning and end of the string?

Original string:

<br>Hello, World! https://www.youtube.com/watch?v=NU7W7qe2R0A<br><br>

Output:

Hello, World! https://www.youtube.com/watch?v=NU7W7qe2R0A

If the original string has <br> tags in the middle of the string, i.e.:

<br>Hello, World!<br><br>https://www.youtube.com/watch?v=NU7W7qe2R0A<br><br>

It should output:

Hello, World!<br><br>https://www.youtube.com/watch?v=NU7W7qe2R0A

How would I achieve this results?

如果给出这样的字符串（例如），我将如何删除所有中断（＆lt; br＆gt; ; 的任何其他格式 code>）标记 em>字符串的开头和结尾？ p>

原始字符串： p> 

 ＆lt; br＆gt; Hello，World！  https://www.youtube.com/watch?v=NU7W7qe2R0A<br><br>
 代码>  PRE> 
 
 
输出： p> 
 
  你好，世界！  https://www.youtube.com/watch?v=NU7W7qe2R0A
nn

如果原始字符串中包含＆lt; br＆gt; code>标签 字符串的中间，即： p> 

 ＆lt; br＆gt; Hello，World！＆lt; br＆gt;＆lt; br＆gt; https：//www.youtube.com/watch？  v = NU7W7qe2R0A＆lt; br＆gt;＆lt; br＆gt; 
  code>  pre> 
 
 
它应输出： p> 
 
 


  Hello，World！＆lt;  ; br＆gt;＆lt; br＆gt; https：//www.youtube.com/watch？v = NU7W7qe2R0A 
  code>  pre> 
 
 
我将如何实现这一结果？ p>  
  div>

答

You could use preg_replace and a regular expression like this.

$s = '<br><br /><Br  ><br   />Hello, World!<br><br />testing 123<br  ><BR   /><br><br />';

$stripped = preg_replace('/^(<br\s*\/?>)*|(<br\s*\/?>)*$/i', '', $s);

var_dump($stripped);

Outputs:

string(57) "Hello, World!<br><br />testing 123"

答

I use this :

<?
$data = '<br>Hello, World!<br><br><br /><br>';
$filter = array('<br>','<br />'); 
$data = str_replace($filter,'',$data);
var_dump($data);

答

To match <br> at the beginning and the end of a string use:

(?:\A<br\s*/?\s*>)+|(?:<br\s*/?\s*>)+$

$result = preg_replace('%(?:\A<br\s*/?\s*>)+|(?:<br\s*/?\s*>)+$%i', '', $text);

A more generalized regex is:

(?:\A<[a-z\d]+\s*/?\s*>)+|(?:<[a-z\d]+\s*/?\s*>)+$

$result = preg_replace('%(?:\A<[a-z\d]+\s*/?\s*>)+|(?:<[a-z\d]+\s*/?\s*>)+$%i', '', $text);

答

This is what I use in my projects :

Code below will handle : <br>, <br >, <br   >, <br/>, <br />, <br   />

$data = "<br><br ><br/><br />test1<br><br  ><br />test2<br><br ><br/><br />";
$str = preg_replace('/^(<br\s*?\/?>)+|(<br\s*\/?>)+$/', '', $data);
echo $str;

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