PHP preg_grep Variable

Question

Using preg_grep, how would you search for an exact match of a variable? I was able to get the following code to return anything containing those letters, but can't seem to get only exact match.

$o is an array $a for example would be "at"

$c=preg_grep("/$a/",$o);
echo implode($c, ' ');

And the output would be something like: at cat hat mat

Using logic from bash grep I thought I could use ^\\$a$ but apparently isn't correct. Any ideas?

Answer 1

Vanilla PHP:

preg_grep('/\b' . preg_quote($a, '/') . '\b/', $o);

You can also use T-Regx

Pattern::inject('\b@\b', [$a])->forArray($o)->filter();