not supports multi-level groupings

[jayvendor]

how to pass multi level groupings
array_group_by($records, 'state', 'city')
giving "Message: call_user_func_array() expects parameter 1 to be a valid callback, function 'array_group_by' not found or invalid function name" error

[tbreuss]

how to pass multi level groupings array_group_by($records, 'state', 'city') giving "Message: call_user_func_array() expects parameter 1 to be a valid callback, function 'array_group_by' not found or invalid function name" error

Be careful if you use the function in a namespace by copying and pasting the function into your own code. Then the namespace must be added when calling call_user_func_array.