remove element from array based on sql query

Question

$_SESSION['lines'] is populated from a textbox that a user pastes into. Before I do anything with the data, I want to run it through a filter to see if any of the values they've input are NOT in the database.

foreach ($_SESSION['lines'] as $q) {
$multiSupplierQuery      = "SELECT distinct supplier from allparts where quotePartNumber = '$q'";
$multiSupplierResult    = mysqli_query($con, $multiSupplierQuery);

while ($row = mysqli_fetch_array($multiSupplierResult)) {
  $multiSupplier = $row['supplier'];
}
 if (!multiSupplier) {
  unset($_SESSION['lines'[]);
 }
}

The crux of this revolves around this statement:

 if (!multiSupplier) {
  unset($_SESSION['lines'[]);
}

What I'm trying to say is: each time we cycle through this, if multiSupplier doesn't exist, remove this particular element from the array.

my unset syntax is wrong though... how do I make it right?

Looks like you have an extra [ at unset($_SESSION['lines'[]). — Paulo Scardine
– Paulo Scardine, Commented Feb 3, 2015 at 21:52

Jo. · Accepted Answer · 2015-02-03 23:39:54Z

2

You probably want to add a $ to your if statement. Change

if (!multiSupplier) {

to

if (!$multiSupplier) {

Also, to unset from the $_SESSION you need a key. Try changing

foreach ($_SESSION['lines'] as $q) {

to

foreach ($_SESSION['lines'] as $key=>$q) {

and then

unset($_SESSION['lines'][$key]);

edited Feb 3, 2015 at 23:39

answered Feb 3, 2015 at 22:08

Jo.

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2 Comments

Brian Powell Over a year ago

Yup - I saw that typo too. Thanks! What's the difference between the answer that @Dagon provided above, unset($_SESSION['lines'][$q]); where no key is used and your answer? After some testing, your solution worked while the one above did not.

Jo. Over a year ago

When using the foreach, $q contains a copy of the item in the $_SESSION array; modifying $q doesn't change $_SESSION at all. Also, $q is not an array key, so it doesn't make sense to try to unset $_SESSION['lines']'s $q key. When you add the $key, it tells you where the actual data is stored in the $_SESSION['lines'] variable so php knows which item to unset.

V13Axel · Accepted Answer · 2015-02-03 21:55:19Z

1

It's not your unset usage, you just have an unnecessary opening square bracket.

unset($_SESSION['lines'[]);

should be

unset($_SESSION['lines']);

And you'll be good to go.

answered Feb 3, 2015 at 21:55

V13Axel

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3 Comments

Brian Powell Over a year ago

no - what this does is it completely unsets the entire 'lines' array that I've made, (e.g. - removes all data from it.) I just want to remove THAT specific element from the entire array if the query comes back with no results.... So - if $_SESSION['lines'] is comprised of 6 elements, and element 3 isn't in the database, I want to remove item 3 from the $_SESSION['lines'] array, but keep items, 1, 2, 4, 5, and 6.

user557846 Over a year ago

then you want unset($_SESSION['lines'][$q]);

Brian Powell Over a year ago

perfect - that's exactly what I needed... the [$q] part. Awesome, thank you!

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