php实现使用正则将文本中的网址转换成链接标签

复制代码 代码如下:
function text2links($str="") {
    if($str=="" or !preg_match("/(http|www.|@)/i", $str)) { return $str; }
    $lines = explode(" ", $str); $new_text = "";
    while (list($k,$l) = each($lines)) {
        // replace links:
        $l = preg_replace("/([ ]|^)www./i", "\1http://www.", $l);
        $l = preg_replace("/([ ]|^)ftp./i", "\1ftp://ftp.", $l);
        $l = preg_replace("/(http://[^ ) !]+)/i",
            "<a href="\1">\1</a>", $l);
        $l = preg_replace("/(https://[^ ) !]+)/i",
            "<a href="\1">\1</a>", $l);
        $l = preg_replace("/(ftp://[^ ) !]+)/i",
            "<a href="\1">\1</a>", $l);
        $l = preg_replace(
            "/([-a-z0-9_]+(.[_a-z0-9-]+)*@([a-z0-9-]+(.[a-z0-9-]+)+))/i",
            "<a href="mailto:\1">\1</a>", $l);
        $new_text .= $l." ";
    }
    return $new_text;
}