Choosing a random character

[teguh123]

Guys, I got a stupid noob question

Say I want to fill variable $query with a random one character string picked randomly from a letter a-z with equal probability.

How would I do so?

So, $query can be 'a', maybe , 'q', maybe whatever, each with 1/26th probability.

Thanks a lot.

[Installer]

$arr = range('a', 'z');
$rand_char = $arr[mt_rand(0, count($arr) - 1)];

[teguh123]

Excelent. Of course, if I work hard I can probably come up with a solution, but my solution won't be as ellegant as those provided by super guru here 😃

[Installer]

Except my original answer won't work. 🙂 See the edited code.

Here's another one:

$arr = range('a', 'z');
$rand_char = $arr[array_rand($arr)];

Or, essentially the same thing:

$arr = array_flip(range('a', 'z'));
$rand_char = array_rand($arr);

[teguh123]

<php>
$arr = array_flip(range('a', 'z'));
$rand_char = array_rand($arr);
</php>

I used this one. It works perfectly. Thanks a lot.

[NogDog]

An "array-free" possibility:

$rand_char = chr(rand(ord('a'), ord('z')));

[teguh123]

better and better.

What about if I want to randomize between a-z and 0-9 each with equal probability?

[NogDog]

I use something like this for generating random "captcha" strings:

$chars = 'abcdefghijklmnopqrstuvwxyz0123456789';
$randChar = $chars[rand(0, strelen($chars) - 1)];

It's not necessarily better/worse than the array-based options, but I found it useful because it was easy to manipulate. For instance, if I want to increase the possibility of a the selected character being a number, and I want to avoid certain characters that could be confusing (o or 0, l or 1, i or j, u or v):

$chars = 'abcdefghkmnpqrstwxyz2233445566778899';

[Installer]

NogDog's solutions are better, but just for interest here's an array-based one:

$arr = array_flip(array_merge(range('a', 'z'), range('0', '9')));
$rand_char = array_rand($arr);

For not array-based, this one will work but is a little clumsy:

$ord = 58;
while (($ord > 57) && ($ord < 97)) {
    $ord = mt_rand(48, 122); 
}
$rand_char = chr($ord);

[teguh123]

So many great solutions

[laserlight]

Personally, I use something like what NogDog described, but Installer's solutions are interesting.