Simple regex match **after** a period?

[JAB Creations]

I'm trying to figure out how to make a regex to match after a period. In example the string 'af24cca.z' would match as 'z', or '24t24.4f' would match as '4f'.

$cookie = 'audio.0_backgroundimages._browserpatch.1';

$my_pattern = '/^(\.){1}/';

list($audio, $backgroundimages, $browserpatch) = split($my_pattern, $cookie);
echo $audio; 

In the script above the desired match in this instance would be '0'.

[Master_script_maker]

$cookie = 'audio.0_backgroundimages._browserpatch.1'; 

$my_pattern = '/^(\.){1}/'; 

list($audio, $backgroundimages, $browserpatch) = split($my_pattern, $cookie); 
echo $audio;

^ means at the beginning of the string meaning you want to split the string at the first character if it is a period.
try

$my_pattern = '/(\.){1}/';

[JAB Creations]

Hmm, nothing is working; any suggestions for a more indepth regex cheat sheet?

[Master_script_maker]

after checking php.net, i think the regex should be [.]

[JAB Creations]

Ah! I see! I was using regex slashes / / though they are unnecessary and prevent the script from operating correctly. I figured it was regex, what's the catch?

[boogyman]

after checking php.net, i think the regex should be [.]

that would match any character, because the dot is a wildcard in terms of regular expressions, I am pretty sure you would need to do
[\.]

Ah! I see! I was using regex slashes / / though they are unnecessary and prevent the script from operating correctly. I figured it was regex, what's the catch?

can you re-phrase that?

/expression/ is what lets the language know that what you are about to declare is a regular expression.