正则表达式和 preg_replace [关闭]

【问题标题】：Regex and preg_replace [closed]正则表达式和 preg_replace [关闭]
【发布时间】：2012-12-16 05:32:50
【问题描述】：

这行是什么意思：

$fields = explode("\r\n", preg_replace('/\x0D\x0A[\x09\x20]+/', ' ', $header));

【问题讨论】：

【解决方案1】：

preg_replace 将展开电子邮件header lines that are split across multiple lines。然后explode 调用会将生成的字符串拆分为一个数组，每个数组单元格有一个标题行。

例如字符串：

Subject: This is a long subject
    line split across
  multiple lines
From: user@example.com

将被preg_replace 转化为：

Subject: This is a long subject line split across multiple lines
From: user@example.com

下面explode会给你：

Array(
    [0] => 'Subject: This is a long subject line split across multiple lines',
    [1] => 'From: user@example.com'
)

【讨论】：