Warning: in_array() expects parameter 2 to be array, null given

Question

I am getting the following warning when trying to add data to a session (and checking if it already exists).

Warning: in_array() expects parameter 2 to be array, null given

How can I fix this?

The code it is referring to:

if(isset($_GET['product']) && !in_array($_GET['product'], $_SESSION['product'])){
    $_SESSION['product'][] = $_GET['product'];
}

I only get this warning when adding the first product on a cleaned browser. When I remove it and add another product the warning is gone. Same if I add a second product.

it seems $_SESSION['product'] dosen't contain any data. Try to print $_SESSION['product'] — Nishant Nair
– Nishant Nair, Commented Jan 10, 2017 at 9:19
may i know which one return an array $_SESSION['product'] or $_GET['product'] ? — lazyCoder
– lazyCoder, Commented Jan 10, 2017 at 9:23
Add a $_SESSION["product"] = $_SESSION["product"]?:[] before the if to initialize the array. Otherwise you'll never add anything to it with this code. — apokryfos
– apokryfos, Commented Jan 10, 2017 at 9:23

malutki5200 · Accepted Answer · 2017-01-10 09:20:24Z

4

The warining says it all. This param is null:

 $_SESSION['product']

Make sure it is set before you use it. Example:

if(isset($_SESSION['product']) && isset($_GET['product']) &&  !in_array($_GET['product'], $_SESSION['product'])){
        $_SESSION['product'][] = $_GET['product'];
    }

answered Jan 10, 2017 at 9:20

malutki5200

1,1128 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Rahul · Accepted Answer · 2017-01-10 09:22:49Z

1

Your $_SESSION['product'] is empty. Try this,

if(!empty($_SESSION['product']) && isset($_GET['product']) && !in_array($_GET['product'], $_SESSION['product'])){
    $_SESSION['product'][] = $_GET['product'];
}

It should work.

answered Jan 10, 2017 at 9:22

Rahul

18.6k7 gold badges43 silver badges64 bronze badges

Comments

LF-DevJourney · Accepted Answer · 2017-01-10 09:23:23Z

1

check if the value is set before use it with isset and use is_array to check if a given variable is an array.

if(isset($_GET['product']) && is_set($_SESSION['product']) && is_array($_SESSION['product']) && !in_array($_GET['product'], $_SESSION['product'])){
    $_SESSION['product'][] = $_GET['product'];
}

answered Jan 10, 2017 at 9:23

LF-DevJourney

28.7k30 gold badges170 silver badges321 bronze badges

Comments

Nishant Nair · Accepted Answer · 2017-01-10 09:25:45Z

1

you should always apply check for array

isset( $_SESSION['product']) in your is condition before & condition

answered Jan 10, 2017 at 9:25

Nishant Nair

1,9971 gold badge14 silver badges18 bronze badges

Collectives™ on Stack Overflow

Warning: in_array() expects parameter 2 to be array, null given

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related