Obj / C：对自定义订单排序数组

I've got an array of NSMutableDictionaries, containing (amongst others) the key Location. I need to sort the array to input it into a table. On top should be N, below should be A, and below that should be R. So in sort: How can I sort an array in the order: N - A - R?I've got an array of NSMutableDictionaries, con