Eliminating Characters using PHP PCRE

If I have a string $random, and I want to throw o开发者_运维百科ut everything except commas and numbers, how could I do this in PHP PCRE?

I know \d will match numbers, but I don't get the rest of PCRE.

Try something like

preg_replace("/[^\d,]/", "", $random);

You can use T-Regx (you don't even need delimiters):

pattern('[^\d,]')->remove($random)->all();

or if you want only to remove the first

pattern('[^\d,]')->remove($random)->first();