$text = "asdfs#sdfj#HELLO123#lj#lj##jlkj#lkjl#lll#lll##jjjjj#";
截取第2-3#之间的数据 HELLO123
截取第N-N+1 #之间的数据,这个N为是已知数
//分页
$test = explode('#',$text);
echo $test[$page-1];
先根据#进行split分组后,再取数据不是更简单?
$text = "asdfs#sdfj#HELLO123#lj#lj##jlkj#lkjl#lll#lll##jjjjj#";
preg_match('/(?:.*#){2}(.+)#/U', $text, $match);
echo $match[1]; //HELLO123