PHP文本换行转
函数nl2br()与nl2p()文本换行转p段落

<?php $str = "Welcome to 
www.scutephp.com";
        
echo nl2br($str);
        
?>

Welcome to <br>
www.scutephp.com

<?php function nl2p($text) {
  return "<p>" . str_replace("\n", "<p>", $text) . "</p>";
}
?>

/**
 * Returns string with newline formatting converted into HTML paragraphs.
 *
 * @param string $string String to be formatted.
 * @param boolean $line_breaks When true, single-line line-breaks will be converted to HTML break tags.
 * @param boolean $xml When true, an XML self-closing tag will be applied to break tags (<br>).
 * @return string
 */
function nl2p($string, $line_breaks = true, $xml = true)
{
    // Remove existing HTML formatting to avoid double-wrapping things
    $string = str_replace(array('<p>', '</p>', '<br>', '<br>'), '', $string);
       
    // It is conceivable that people might still want single line-breaks
    // without breaking into a new paragraph.
    if ($line_breaks == true)
        return '<p>'.preg_replace(array("/([\n]{2,})/i", "/([^>])\n([^\n</p><p>", '<br true :>'), trim($string)).'</p>';
    else
        return '<p>'.preg_replace("/([\n]{1,})/i", "</p>\n<p>", trim($string)).'</p>';
}