assign a matched group values into the variable in php

Using php how to split the usernames,passwords,datadasename,hostname,etc into a variable.

For Example:

$db = "databasename://username:password@hostname/dbname"

$ databasename = databasename

$user = username

$pass = password

$host = hostname

$dbname = dbname

I have tried with grouping in regular expression. but I don't know how to assign the group values into the variable.

preg_match("(开发者_JS百科^([a-z]?)://([a-z]?):([a-z]?)@[a-z]?)/([a-z]*?)$)", $db , $matches);

You can do something like:

$db = "databasename://username:password@hostname/dbname";
if (preg_match("~^([a-z]+)://([a-z]+):([a-z]+)@[a-z]+/([a-z]+)\$~i",
        $db , $matches))
   list($ignore, $databasename, $username, $password, $dbname) = $matches;

var_dump($databasename);
var_dump($username);
var_dump($password);
var_dump($dbname);

which gives:

string(12) "databasename"
string(8) "username"
string(8) "password"
string(6) "dbname"

Or you can use named groups.

Look at

 print_r($matches);

after successful match. It should become clear.

From php docs here http://pl2.php.net/preg_match :

If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.

You have to pick a delimiter (typically, a character that is not used with the expression). The expression should start and end with the delimiter and you can optionally append flags after the closing deliminiter. E.g.:

preg_match("~(^([a-z]?)://([a-z]?):([a-z]?)@[a-z]?)/([a-z]*?)$)~i", $db , $matches);

You should consider to widen most character ranges: a username can contain numbers and a password can contain almost anything.

I suppose that the delimiters in the string (:, //, @...) won't necessarily be there if the corresponding parameters are optional.

Last but not least, as Kamil Szot already pointed out, parenthesized matches are loaded into the $matches variable.

php > preg_match("#([a-z]+)://([a-z]+):([a-z]+)@([a-z]+)/([a-z]+)$#", $var , $matches);

php > print_r($matches);

Array ( [0] => databasename://username:password@hostname/dbname [1] => databasename [2] => username [3] => password [4] => hostname [5] => dbname )