It is interesting that you pose the question in regard to SPL instead of a data structure consideration.  But still, while array is a viable structure for many applications, SPL is not the only language that has to go to extra length to handle.  If you have a choice, and if you don't care much about front-end compute, hash is easier on SPL. (And again, easier in some use cases with other languages.) I do want to suggest, though, you drop the nested listX.id node because that is redundant. (Lastly, I also recommend that you illustrate with compliant JSON.  This makes volunteers work easier.) {"host": "test", "list1" :{                   "ip": "192.168.0.1",                    "device": "laptop",                    "value": 123              }, "list2" : {                    "ip": "192.168.0.2",                    "device": "phone",                    "value": 1223                    }, "list3":   {                    "ip": "192.168.0.3",                    "device": "desktop",                    "value": 99                    } } ... View more