删除字符串前的 <br /> 标签

Question

我正在使用我的 php 从电子邮件正文中获取电子邮件数据。我在删除<br />字符串之前的标签时遇到了问题This message was created。这是完整的电子邮件正文：<br /><br />This message was created automatically by mail delivery software.<br /><br />A message that you sent could not be delivered to one or more of its<br />recipients. This is a permanent error. The following address(es) failed: <br /><br />   [e-mail]<br />      retry timeout exceeded我试过这个：$top_message = str_replace('<br /> <br /> This message', 'This message', $top_message);我也试过这个：$top_message = str_replace('<br /> <br />', '', $top_message);它不会<br />在字符串之前删除标签，也不会发生任何事情。这是完整的代码：$body = imap_body($mailbox, $email_number, 2);$email_body = utf8_decode(imap_utf8($body));$top_message = getBetween($email_body, 'charset=us-ascii', 'exceeded') . 'exceeded';       $top_message = nl2br($top_message);$top_message = str_replace('<br /> <br /> This message', 'This message', $top_message);echo $top_message我想要实现的是，当我从电子邮件正文中获取电子邮件数据时，我想用来为每一行nl2br添加<br />标签，然后我想删除<br />字符串之前的两个标签This message was created。我想让它显示如下：This message was created automatically by mail delivery software.<br /><br />A message that you sent could not be delivered to one or more of its<br />recipients. This is a permanent error. The following address(es) failed: <br /><br />   [e-mail]<br />      retry timeout exceeded你能告诉我一个例子我如何能够<br />在字符串之前删除两个标签吗？谢谢你。

Answer 1

使用preg_replace与以下正则表达式：/^(<br\s*\/>\s*)*/。

它将删除<br/>消息开头的所有标签。

$str = "<br />

<br />

This message was created automatically by mail delivery software.<br />

<br />

A message that you sent could not be delivered to one or more of its<br />

recipients. This is a permanent error. The following address(es) failed: 

<br />

<br />

   [e-mail]<br />

      retry timeout exceeded";

print_r(preg_replace('/^(<br\s*\/>\s*)*/', '', $str));

输出：

This message was created automatically by mail delivery software.<br />

<br />

A message that you sent could not be delivered to one or more of its<br />

recipients. This is a permanent error. The following address(es) failed: 

<br />

<br />

   [e-mail]<br />

      retry timeout exceeded

Answer 2

您可以使用 ltrim() 它将根据字符掩码删除字符。
意味着 any<和 anyb以及 anyr和/any>直到它找到不同的字符。

$message = ltrim($message, "<br/> ");

我添加了空间也是因为它无论如何都是“可选的”。

请注意，如果我的评论的答案是否定的，这将不起作用，这意味着该消息并不总是以“此消息..”开头。
因为如果字符串是"<br> <br> break free..."输出将是"eak free..."因为字符掩码将删除“break”中的“br”。
如果单词以“rb”开头，它也会删除。

Answer 3

看起来您在 <br> 之间有一个换行符 (\n)。请试试这个：

$top_message = str_replace("/software\.<br \/>\n<br \/>/", 'software.', $top_message);