PHP 正则表达式匹配字符串中的uid值

可以使用正则表达式来匹配字符串中的uid后的内容。以下是一个示例代码：

$str = '{"mp":{"autoplay":"1","loop":"0","muted":"0","lang":"zh-cn","volume":"0.8","live":"0","autoOrientaion":"1","dragSpotShape":"0","closeControlsTimer":"3500","showMiniProgress":"1","contextmenu":"\u8d85\u7ea7\u64ad\u653e\u5668$https:\/\/www.maccmsbox.com\/details371.html"},"plyr":{"settings":"1","pip":"1","airplay":"1","fullscreen":"1","keyboard":"1","autoplay":"1","volume":"0.8","muted":"0","i18n":{"speed": "\u64ad\u653e\u901f\u5ea6","normal": "\u6b63\u5e38"}},"uid":"OB0iBp"}';

preg_match('/"uid":"(.*?)"/', $str, $matches);
$uid = $matches[1];

echo $uid;

运行以上代码将输出字符串OB0iBp。