Question

When I echo the contents of the $_GET variable, there are two values that weren’t even in the link.

array (
'__utma' => '118264987.369913698.1357785187.1358515273.1358367728.77',
'__utmz' => '118254987.1328042362.21.9.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=(not provided)',
)

How can I reliably strip the $_GET variable of all this useless data?

Answer 1

You can remove the “offending” array keys like this:

// only use the keys that we want
$keys = preg_grep('/^__utm.$/', array_keys($_GET), PREG_GREP_INVERT);
// get the values that belong to those keys
$values = array_intersect_key($_GET, array_flip($keys));

It removes (or rather skips) the keys that start with __utm and are followed by exactly one character.

Btw, you can change the pattern to be more restrictive, such as:

^__utm[az]$

This will only remove __utma and __utmz but not __utmx for instance.