unset multidimensional array

Question

I am having a hell of a time with this. I have a multidimensional array that I am storing in a session.

$d1 = array(1,2,3,4);
$d2 = array(1,2,3,4,5,6);
$d3 = array(1,2,3,4,5,6,7,8);
$d4 = array(1,2,3,4,5);
$_SESSION['array1'] = array($d1,$d2,$d3,$d4);

what I want to do is remove the $d2 array from the session array1

however when I do something like this

unset($_SESSION['array1'][1]);

you would think that $_SESSION['array1'] would then = array($d1,$d3,$d4);

however what that does is actually unset the whole session variable.

Then if I try something like

foreach ($_SESSION['array1'] as $k => $v) {
echo "The Key is $k: The Value is $v";
}

however that gives me an error

Invalid argument supplied for foreach()

The only conclusion that I can come to is that the session variable is being completely unset, not that just the specific key is being removed from the array.

is there any way that i can unset a specific value contained within an array that is part of a session variable?

There must be something else wrong in the code. Try commenting out the `unset(...)` line and `var_dump`ing the `$_SESSION`. — Tomáš Zato, Jan 28 '14 at 00:03

score 1 · Accepted Answer · answered Jan 28 '14 at 00:11

Code you present works as expected:

header("Content-Type: text/plain");
session_start();
$d1 = array(1,2,3,4);
$d2 = array(1,2,3,4,5,6);
$d3 = array(1,2,3,4,5,6,7,8);
$d4 = array(1,2,3,4,5);
$_SESSION['array1'] = array($d1,$d2,$d3,$d4);
unset($_SESSION['array1'][1]); 
print_R($_SESSION);

Prints:

Array
(
    [array1] => Array
        (
            [0] => Array
                (
                    ...
                )

            [2] => Array
                (
                    ...
                )

            [3] => Array
                (
                    ...
                )

        )

)

So some debugging ideas:

Don't use @session_start.
Set error_reporting(E_ALL)
Configure error reporting in php.ini
Check your cookies to see whether the PHPSESSID cookie was sent at all.

thanks, I fogot to do session_start at the beginning of the script — user3005635, Jan 28 '14 at 00:20
Please, still have a look at sємsєм's answer. It's good to have arrays ordered like `(0, 1, 2 ...)`. `unset` does not keep that. — Tomáš Zato, Jan 28 '14 at 00:21

score 1 · Answer 2 · answered Jan 28 '14 at 00:11

1

Use array_splice as the following code shows:

$_SESSION['array1'] = array_splice($_SESSION['array1'],1,0);

answered Jan 28 '14 at 00:11

SaidbakR

13,303
20
101
195

Very good point, unset leaves one offset skipped: `(0, 2, ...)` – Tomáš Zato Jan 28 '14 at 00:13

score 0 · Answer 3 · answered Jan 28 '14 at 00:05

0

How about storing your session variable again:

$_SESSION['array1'] = array($d1,$d3,$d4);

answered Jan 28 '14 at 00:05

Nicoli

643
1
7
23

unset multidimensional array

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