<?php
$users = [
	['name'=>'John Smith', 'birthday'=>'1988-02-03'],
	['name'=>'Jane Jones', 'birthday'=>'2014-07-08']
];
// Calculate and store the age in years of each user
foreach($users as &$user) {	
	$today = new DateTime();
	$birthday = new DateTime($user['birthday']);
	$age = $today->diff($birthday);
	$user['age'] = $age->format("%y");
}
unset($user);
?>
 
$users = [
	['name'=>'John Smith', 'birthday'=>'1988-02-03'],
	['name'=>'Jane Jones', 'birthday'=>'2014-07-08']
];
 
foreach($users as $index => $user) {
	$users[$index]['age'] = calculateAge($user['birthday'])->format("%y");
}
 
var_dump($users);
 
function calculateAge($date) {
	return date_diff(date('Y-m-d'), date_create($date));
}
 
/*EOF*/

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