unset

Preface: I do know how 'unset' works in the userland, but I would like to find out how it works internally. When unset is called on zval structure , it decreases the reference counter (refcount__gc). When refcount__gc reaches 0, the variable is no longer used and can be deleted. The question is whether it's always done immediately, or in some cases it can be done later by garbage collector? I have found two contradictory statements on this: unset() does just what it's name says - unset a variable. It does not force immediate memory freeing. PHP's garbage collector will do it when it see fits -

I am working with a PHP loop, and I had one question regarding how unset affects the array keys. This array uses the standard numeric keys assigned by PHP, 0, 1, 2, 3 etc... . Whenever unset() runs on an array value, are the array keys shuffled or are they maintained as before? Thank you for your time. The keys are not shuffled or renumbered. The unset() key is simply removed and the others remain. $a = array(1,2,3,4,5); unset($a[2]); print_r($a); Array ( [0] => 1 [1] => 2 [3] => 4 [4] => 5 ) Test it yourself, but here's the output. php -r '$a=array("a","b","c"); print_r($a); unset($a[1]);

This question already has an answer here: How do you remove an array element in a foreach loop? 8 answers I'm accessing an array by reference inside a foreach loop, but the unset() function doesn't seem to be working: foreach ( $this->result['list'] as &$row ) { if ($this_row_is_boring) { unset($row); } } print_r($this->result['list']); // Includes rows I thought I unset Ideas? Thanks! You're unsetting the reference (breaking the reference). You'd need to unset based on a key: foreach ($this->result['list'] as $key => &$row) { if ($this_row_is_boring) { unset($this->result['list'][$key]); } }

I've tried searching the php manual and internet on how to delete cookies and I've tried it the exact same way they all say: setcookie("name", '', 1); or setcookie("name", '', time()-3600); But when I check the cookies in the cookies dialog in Firefox, it's still there with the same value. I set this cookie using the following line: setcookie("name", $value, time() + 259200, $path); I found this question on stackoverflow: , but none of the answers solved the problem. I also tried putting all paramaters in, like the author said, but it had no effect. Does anyone see the problem? The manual

Before installing gnuplot, I set the environment variable GNUPLOT_DRIVER_DIR = /home/gnuplot/build/src . During the installation, something went wrong. I want to remove the GNUPLOT_DRIVER_DIR environment variable. How can I achieve it? unset is the command you're looking for. unset GNUPLOT_DRIVER_DIR Walkthrough of creating and deleting an environment variable in bash: Test if the DUALCASE variable exists: el@apollo:~$ env | grep DUALCASE el@apollo:~$ It does not, so create the variable and export it: el@apollo:~$ DUALCASE=1 el@apollo:~$ export DUALCASE Check if it is there: el@apollo:~$ env |