php 如何用新行替换所有 XHTML/HTML 换行符 (<br>)？
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How to replace all XHTML/HTML line breaks (<br>) with new lines?
提问by markb
I am looking for the best br2nlfunction. I would like to replace all instances of <br><br />\n. Much like the nl2br()function but the opposite.
我正在寻找最好的br2nl功能。我想更换的所有实例<br><br />\n。很像nl2br()函数，但相反。
I know there are several solutions in the PHP manual comments but I'm looking for feedback from the SO community on possible solutions.
我知道 PHP 手册注释中有几种解决方案，但我正在寻找来自 SO 社区的关于可能解决方案的反馈。
回答by Pascal MARTIN
I would generally say "don't use regex to work with HTML", but, on this one, I would probably go with a regex, considering that <br>tags generally look like either :
我通常会说“不要使用正则表达式来处理 HTML”，但是，在这一点上，我可能会使用正则表达式，考虑到<br>标签通常看起来像：
<br>- or
<br/>, with any number of spaces before the/
<br>- 或
<br/>, 前面有任意数量的空格/
I suppose something like this would do the trick :
我想这样的事情可以解决问题：
$html = 'this <br>is<br/>some<br />text <br />!';
$nl = preg_replace('#<br\s*/?>#i', "\n", $html);
echo $nl;
Couple of notes :
几个注意事项：
- starts with
<br - followed by any number of white characters :
\s* - optionnaly, a
/:/? - and, finally, a
> - and this using a case-insensitive match (
#i), as<BR>would be valid in HTML
- 以。。开始
<br - 后跟任意数量的白色字符：
\s* - 可选地，一个
/：/? - 最后，一个
> - 并且使用不区分大小写的匹配 (
#i)，<BR>这在 HTML 中是有效的
回答by Antti
You should be using PHP_EOLconstant to have platform independent newlines.
您应该使用PHP_EOL常量来获得独立于平台的换行符。
In my opinion, using non-regexp functions whenever possible makes the code more readable.
在我看来，尽可能使用非正则表达式函数会使代码更具可读性。
$newlineTags = array(
'<br>',
'<br/>',
'<br />',
);
$html = str_replace($newlineTags, PHP_EOL, $html);
I am aware this solution has some flaws, but wanted to share my insights still.
我知道这个解决方案有一些缺陷，但仍然想分享我的见解。
回答by VolkerK
If the document is well-formed (or at least well-formed-ish) you can use the DOM extensionand xpath to find and replace all br elements by a \n text node.
如果文档格式良好（或至少格式良好），您可以使用DOM 扩展和 xpath 查找所有 br 元素并将其替换为 \n 文本节点。
$in = '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html><head><title>...</title></head><body>abc<br />def<p>ghi<br />jkl</p></body></html>';
$doc = new DOMDOcument;
$doc->loadhtml($in);
$xpath = new DOMXPath($doc);
$toBeReplaced = array();
foreach($xpath->query('//br') as $node) {
$toBeReplaced[] = $node;
}
$linebreak = $doc->createTextNode("\n");
foreach($toBeReplaced as $node) {
$node->parentNode->replaceChild($linebreak->cloneNode(), $node);
}
echo $doc->savehtml();
prints
印刷
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head><title>...</title></head>
<body>abc
def<p>ghi
jkl</p>
</body>
</html>
edit: shorter version with only one iteration
编辑：只有一次迭代的较短版本
$in = '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html><head><title>...</title></head><body>abc<br />def<p>ghi<br />jkl</p></body></html>';
$doc = new DOMDOcument;
$doc->loadhtml($in);
$xpath = new DOMXPath($doc);
$linebreak = $doc->createTextNode("\n");
foreach($xpath->query('//br') as $node) {
$node->parentNode->removeChild($node);
}
echo $doc->savehtml();
