PHP正则替换第一位为0。被忽略

Question

$subject='0300020F005176C5A11A730004F955A2A20CD8-367C-EC5B-9D8C-2CAA0B8FE45D';
echopreg_replace('/^(\w{8})\w{2}/i','$1'.'08',$subject);
//输出结果：85176C5A11A730004F955A2A20CD8-367C-EC5B-9D8C-2CAA0B8FE45D
//期望结果：0300020F085176C5A11A730004F955A2A20CD8-367C-EC5B-9D8C-2CAA0B8FE45D
//但是：preg_replace('regex','$1'.'__',$subject);这样是没有问题的

Answer 1

echopreg_replace_callback('/^(\w{8})(\w{2})/i',create_function(//singlequotesareessentialhere,//oralternativeescapeall$as\$'$matches','return$matches[1].\'08\';'),$subject);这样,callback处理