Increment or create a numeric value in an array

Increment or create a numeric value in an array

I want to create or increment a value for a key in an array. So for
example if I have a key 'money' I can increment it in the array by a set
value, or create it if it doesn't exist yet. Currently I'm doing this
which seems a long way of going about it.
if(array_key_exists("money", $account_array)) {
$account_array["money"] = $account_array["money"] + $increase;
}
else {
$account_array["money"] = $increase;
}