正则表达式后向引用 PHP code$reg = "/(\d{2})\/(\d{2})\/(\d{4})/e";$text = '01/25/2009到02/02/2009';$replace = "\${3},\${1}";echo preg_replace($reg, $replace, $text); 报错:syntax error, unexpected ','如果将逗号去掉,输出“200901到200902 ”把逗号换成别的符号也都会报错~------解决方案--------------------把e去掉