$re = '/(?:\G(?!^)",|"groups":\s*\[)\s*"\K[^"]+/m';
$str = '{
"policyItems": [
{
"accesses": [
{
"type": "submit-app",
"isAllowed": true
}
],
"users": [],
"groups": [
"Application_Team_1",
"team2"
],
"conditions": [],
"delegateAdmin": false
}
]
}';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php