Array as session variable

Yes, you can put arrays in sessions, example:

$_SESSION['name_here'] = $your_array;

Now you can use the $_SESSION['name_here'] on any page you want but make sure that you put the session_start() line before using any session functions, so you code should look something like this:

 session_start();
 $_SESSION['name_here'] = $your_array;

Possible Example:

 session_start();
 $_SESSION['name_here'] = $_POST;

Now you can get field values on any page like this:

 echo $_SESSION['name_here']['field_name'];

As for the second part of your question, the session variables remain there unless you assign different array data:

 $_SESSION['name_here'] = $your_array;

Session life time is set into php.ini file.

More Info Here

<?php // PHP part
    session_start();          // Start the session
    $_SESSION['student']=array(); // Makes the session an array
    $student_name=$_POST['student_name']; //student_name form field name
    $student_city=$_POST['city_id'];   //city_id form field name
    array_push($_SESSION['student'],$student_name,$student_city);   
    //print_r($_SESSION['student']);
?>

<table class="table">     <!-- HTML Part (optional) -->
    <tr>
      <th>Name</th>
      <th>City</th>
    </tr>
                                                        
    <tr>
     <?php for($i = 0 ; $i < count($_SESSION['student']) ; $i++) {
     echo '<td>'.$_SESSION['student'][$i].'</td>';
     }  ?>
    </tr>
</table>

First change the array to a string by using implode() function. For Ex :

$number = array(1,2,3,4,5);

# Implode into a string using | as the separator.
$stringofnumber = implode('|', $number);

# Pass the string to a session. e.g
$_SESSION['string'] = $stringofnumber;

So when you go to the page where you want to use the array, just explode your string. For Ex :

# Required before $_SESSION can be accessed.
session_start();

# Explode back to an array using | as the needle.
$number=explode('|', $_SESSION['string']);

You array is now the value of $number.