Delete index session in PHP - php

Question

I have question referring to the session in PHP.
I've coded in PHP for setting the session and I want to delete it , but I got some errors and confusing with using the UNSET(variable $_SESSION). Perhaps anyone could help me to show what should I do with this matter. Thanks in advance
$_SESSION['chart'] = array();
$_SESSION['chart'][0]['index'] = 0
$_SESSION['chart'][0]['type'] = $type;
$_SESSION['chart'][0]['idanimal'] = $iddog;
$_SESSION['chart'][0]['price'] = $price;
printdata(); // <== this is the function to print out the data
All I want to do is just delete based on the index in this session
Here's the function :
function printdata()
{
$totalharga = 0;
if(is_array($_SESSION['chart']))
{
echo "<h3>"."Berikut adalah keranjang belanja anda" . "</h3>". "<br>";
$max = count($_SESSION['chart']);
$th1 = "<th>" . "No" . "</th>";
$th2 = "<th>" . "Animal Type" . "</th>";
$th3 = "<th>" . "ID Binatang" . "</th>";
$th4 = "<th>" . "Harga" . "</th>";
$th5 = "<th>" . "Hapus Data" . "</th>";
echo "<table border=1>";
echo "<tr>";
echo $th1 ;
echo $th2;
echo $th3;
echo $th4;
echo $th5;
echo "</tr>";
for ($indexo = 0; $indexo < $max; $indexo++)
{
echo "<tr>";
echo "<td>" . $indexo."</td>";
echo "<td>" . $_SESSION['chart'][$indexo]['type']."</td>";
echo "<td>" . $_SESSION['chart'][$indexo]['idanimal']."</td>";
echo "<td>" . "Rp. " . $_SESSION['chart'][$indexo]['harga']. ",-" ."</td>";
echo "<td>" . "<a href='deletesession.php?session=$indexo'>" ."Proses ". "</a>"."</td>";
$totalharga += $_SESSION['chart'][$indexo]['harga'];
echo "</tr>";
}
echo "</table>" . "<br/>";
echo "<blockquote>" . "Total Pembelian Item Yang Anda Pesan =". "<h2>". "Rp." . $totalharga . ",-" ."</h2>" . "</blockquote>";
}else
{
echo "Chart is still Empty";
}
}
I've already tried this :
Suppose that there is a chart already filled by the contents then I tried to delete within this code, I've received error with the unset variable
unset($_SESSION['chart'][1])
Thank you

Answer 1

I spot several things that could be improved in your code:
Don't echo in your functions, return instead (then echo what the function returns). This gives you more flexibility regarding what you do with your result.
PHP has a built-in loop for iterating arrays, the foreach loop. You should be using that instead of for.
So here's what I have:
function print_session_data($session) {
if (!is_array($session)) {
return "Array is empty";
}
$table_data = "";
$total_harga = 0;
foreach ($session as $index => $data) {
$table_data .= <<<TABLE_DATA
<tr>
<td>$index</td>
<td>{$data["type"]}</td>
<td>{$data["idanimal"]}</td>
<td>Rp. {$data["harga"]}</td>
<td>Proses</td>
</tr>
TABLE_DATA;
$total_harga += $data["harga"];
}
$result = <<<RESULT
<h3>Berikut abalah keranjang belanja anda</h3>
<table border="1">
<thead>
<tr>
<th>No</th>
<th>Animal Type</th>
<th>ID Binatang</th>
<th>Harga</th>
<th>Hapus Data</th>
</tr>
</thead>
<tbody>
$table_data
</tbody>
</table>
<blockquote>Total Pembelian Item Yang Anda Pesan = <strong>Rp. $total_harga</strong></blockquote>
RESULT;
return $result;
}
$_SESSION['chart'] = array();
$_SESSION['chart'][0]['type'] = "Type";
$_SESSION['chart'][0]['idanimal'] = 6;
$_SESSION['chart'][0]['price'] = '$25';
$_SESSION['chart'][0]['harga'] = 25;
echo print_session_data($_SESSION["chart"]); // <== this is the function to print out the data

Answer 2

Suppose that there is a chart already filled by the contents then I
tried to delete within this code, I've received error with the unset
variable unset($_SESSION['chart'][1])
From what I can see from your code the best way to unset the data correctly is as follow:
DEMO.
You have to check if the $_SESSION['chart'][0] was set before using the session variable index again. If it $_SESSION['chart'] array still contains other indexes then you can call printdata(); else indicate that the session was empty.