$p = '/(\w+\s\w+)/';//这个括号是分组的意思吗？

Question

$p = '/(\w+\s\w+)/';//加括号，$match有两个$n ='/\w+\s\w+/';//不加括号，$mctch有就只有一个$str = "name:steven jobs";preg_match($p, $str, $match);preg_match($n, $str, $mctch);print_r($match);echo "<br/>";print_r($mctch);Array ( [0] => steven jobs [1] => steven jobs ) Array ( [0] => steven jobs )

Answer 1

子模式匹配分组，可以反向引用，替换，查找