php反向引用出错？

Question

php反向引用出错？<?php$class_sheet=array("post","read-more");
$css_merge_str="body{}.post{color:red;}.hello{text-align:left;}.read-more{color:yellow;}";
$css_arr=array();foreach($class_sheet as $k=>$v){
preg_match_all("#(?<=\})([^\}\{])*\.{$v}\\2*\{\\2*\}#isU",$css_merge_str,$result);
// preg_match_all("#(?<=\})([^\}\{])*\.{$v}\\1*\{\\1*\}#isU",$css_merge_str,$result);
// preg_match_all("#(?<=\})([^\}\{])*\.{$v}([^\}\{])*\{([^\}\{])*\}#isU",$css_merge_str,$result); $css_arr=array_merge($css_arr,$result[0]);
// print_r($result[0]);
}?>

Answer 1

想要的东西
.post{color:red;}.read-more{color:yellow;}