Create nested arrays from specific variables within session - php

Question

I have several values stored in $_SESSION beginning with 'first_name_' & 'last_name_' which then a number appended to the end deepening on how many names are generated.
I am able to extract each of these values from the session and add to an array but would like to pair up the first and last names together within a nested array. (if that makes sense)
at the moment I have:
$users_array = array();
foreach ($_SESSION as $key => $value) {
if(strpos($key, 'first_name_') === 0) {
$users_array[] = $value;
}
if(strpos($key, 'last_name_') === 0) {
$users_array[] = $value;
}
}
This produces an output with var_dump:
array
0 => string 'John' (length=4)
1 => string 'Smith' (length=8)
2 => string 'Jane' (length=4)
3 => string 'Doe' (length=3)
But what I would like is something like:
array
'user' =>
array
'first_name' => string 'John' (length=4)
'last_name' => string 'Smith' (length=5)
array
'first_name' => string 'Jane' (length=4)
'last_name' => string 'Doe' (length=5)
Any suggestions on how I can achieve this?

Answer 1

deceze is right in his comment... But just so people with similar issues with creating 2-dimensional array from a 1-dimensional array, here is a solution. Also, note that PHP does not guarantee that the order will be same when iterating using FOREACH. As this will work, it is still prone to errors.
$users_array = array();
foreach ($_SESSION as $key => $value) {
if(strpos($key, 'first_name_') === 0) {
$users_array[] = array();
$users_array[count($users_array)-1]['first_name'] = $value;
}
if(strpos($key, 'last_name_') === 0) {
$users_array[count($users_array)-1]['last_name'] = $value;
}
}