in PHP string, how to convert non-alphanumeric characters to ascii in hex

For example, how to write a PHP function to convert

http://abc.com/hi-1?source=google

to be converted into

http%3A%2F%2abc.com%2Fhi-1%3Fsource%3Dgoogle

P.S. some exception should be开发者_Go百科 not be converted, like '.' '-'

Thanks.

http://php.net/manual/en/function.urlencode.php
or
http://www.php.net/manual/en/function.rawurlencode.php

<?php
$string = "http://abc.com/hi-1?source=google";
echo urlencode($string); //echo rawurlencode($string);

http://php.net/manual/en/function.rawurlencode.php

echo rawurlencode("http://abc.com/hi-1?source=google");