Need to unset a specific session array - php

Question

I have set an array to a session variable using key-value pairs, but I need to unset that specific session when I click on the delete button.
This is the code that stores the session variables:
$_SESSION['product'][] = array(
'product_id' => $part_id,
'title' => $title,
'price' => $price,
'default_img' => $default_img,
'quantity' => $quantity);
And here's the code that unsets the session:
if (isset($_POST['removeItem'])) {
$prodId=$_SESSION['prodItemId'];
foreach($_SESSION['product'] as $item) {
if ($_GET["partid"] == $item['product_id']) {
unset($_SESSION["product"]);
}
The problem I'm having is that instead of just unsetting one session instance, it unsets the entire session. I've tried unset($_SESSION["product"][$item]);

Answer 1

You tell the code to unset the whole session, so it does.
Include the key in the foreach and unset the specific key that you need to unset.
foreach($_SESSION['product'] as $key => $item) {
if ($_GET["partid"] == $item['product_id']) {
unset($_SESSION["product"][$key]);
}
}
You could also search for the specific value and skip the whole loop thing.
if (isset($_POST['removeItem'])) {
$prodId=$_SESSION['prodItemId'];
$key = array_search($_GET["partid"], array_column($_SESSION['product'], 'product_id'));
if($key !== false) unset($_SESSION["product"][$key]);
}
Array_search searches for the GET partid and if it's found it returns the key of where it is, else it returns false.
If you have multiple array items that need to be removed the above array_search method will only remove the first.
You can however loop the array_search to get them all.
if (isset($_POST['removeItem'])) {
$prodId=$_SESSION['prodItemId'];
$prodID = array_column($_SESSION['product'], 'product_id'); // creates a flat array that can be searched
while($key = array_search($_GET["partid"], $prodID)){
unset($_SESSION["product"][$key]);
}
}
Here we search to see if there is a matching value, if there is we delete the key, then the while loop searches again.
If a new matching value is forum it's deleted, if not array_search will return false and break the while loop.
A fourth method is to almost keep the code you have as it is, but loop the array by reference with & and unset the item.
foreach($_SESSION['product'] as &$item) { // notice the &
if ($_GET["partid"] == $item['product_id']) {
unset($item); //because we used &, we can now unset $item
}
}
A fifth method is to use array_diff and array_intersect.
This method is the slowest and should not be used on larger arrays, it can be used with very little difference on smaller arrays (less than 50-100 items).
if (isset($_POST['removeItem'])) {
$prodId=$_SESSION['prodItemId'];
$_SESSION['product'] = array_intersect_key($_SESSION['product'], array_diff(array_column($_SESSION['product'], 'product_id'), $_GET["partid"]));
}
In order to explain it I need to explain it in "reverse" order from what you read it since it's nested.
I start with created a flat array with array_column.
This array only contains the productid's.
I use array_diff to return only the items that is not matching $_GET["partid"].
What we get is a flat array with only the productid's. That may sound useless, and it is, but the keys is useful.
The keys match what is in the session array.
So if we use array_intersect_key and use $_SESSION['product'] as the main array and the keys from the array_diff then the output is the items in $_SESSION['product'] that does not match $_GET["partid"].
It's complicated in the background but it's a simple on liner.