Re: Re: rand_str

This sort of function should be implemented in PHP. It doesn't say good things about a language when such trivial functionality needs to be implemented non-natively. And it doesn't need to be: function str_rand($len = 8, $class = 'a..zA..Z0..9') { if (!preg_match_all('/(.)\.\.(.)/', $class, $matches)) { return ''; } $chars = array(); $m1 = $matches[1]; $m2 = $matches[2]; for ($i = 0; $i < count($m1); $i++) { $chars = array_merge($chars, range(ord($m1[$i]), ord($m2[$i]))); } if (($nchars=count($chars)) == 0) { return ''; } else if ($nchars == 1) { return str_pad('', $len, chr($chars[0])); } $str = ''; for ($i = 0; $i < $len; $i++) { $str .= chr($chars[mt_rand(0, $nchars-1]); } return $str; } A translation into C might run about 100 times faster. In most applications, that doesn't justify sacrificing the flexibility and safety of a native implementation. On a related note, I don't see why PHP shouldn't ship with a standard library written in PHP. -Dan ----- Original Message ----- From: "Cynic" <cynic@mail.cz> To: "Jeroen van Wolffelaar" <jeroen@a-eskwadraat.nl> Cc: "PHP Developers Mailing List" <php-dev@lists.php.net> Sent: Sunday, August 05, 2001 5:16 PM Subject: Re: [PHP-DEV] Re: rand_str > At 22:50 8/5/2001, Jeroen van Wolffelaar wrote the following: > -------------------------------------------------------------- > >> >Implementing something that has NOT that limitation, is far less trivial. > >> > >> function str_rand($len = 8, $class = 'a-zA-Z1-9') > >> { > >> static $init = 1; > >> if(1 == $init){ > >> mt_srand((double) microtime() * 1000000); > >> $init = 0; > >> } > >> $chars = array(); > >> for($i = 0; $i < $len; $i++){ > >> $chars[] = chr(mt_rand(0,255)); > >> } > >> return implode('', > >> preg_grep('|['.preg_quote($class).']|',$chars)); > >> } > >> > >> Just a little bit different syntax for the second argument. > >> What's the big deal? :) > > > >Okay, but hey, you're a PHP-expert with probably many years of experience... > > Faaaar from that. :) > > >By the way, your function won't return strings of length $len... ;) > > Oh, shit. Optimization instead of a function. :) > I've been sitting before the CRT for 30 hours... > > >And you could say that preg_grep is quite a hack. > > Well, it nicely fits the bill - if you use the second argument as > a character class, preg_quote/grep() lends itself. Or do you mean the > concatenation? That's just a matter of formatting. Take it out of the > preg_grep() call, and it'll look better. > > >Anyway, this didn't convince me it's trivial... I'm sorry. > > ok. :) seems like the only function that'll be missing from PHP > will be write_the_app(); :))) > > But this is really a non-issue. I'm fine with or without str_rand(), > I was just trying to show that it's pretty easy to write one in PHP, > and so the function isn't really necessary. I know, there's nl2br() > which _is_ simple, but that's backed by the fact that in a web-oriented > language, _everybody_ would write their own nl2br(). This is not the > case with str_rand()... > > And now help me down off that soap box. :) > > > > > cynic@mail.cz > ------------- > And the eyes of them both were opened and they saw that their files > were world readable and writable, so they chmoded 600 their files. > - Book of Installation chapt 3 sec 7 > > > -- > PHP Development Mailing List <http://www.php.net/> > To unsubscribe, e-mail: php-dev-unsubscribe@lists.php.net > For additional commands, e-mail: php-dev-help@lists.php.net > To contact the list administrators, e-mail: php-list-admin@lists.php.net > >