我正在使用返回以下JSON的服务：
{
"Airport Terminal A Departures: October 6, 2014, 8:31 pm": [
{
"Northbound": [
{
"direction": "N",
"path": "R4N",
"train_id": "462",
"origin": null,
"destination": "Warminster",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 08:43:00:000PM",
"depart_time": "Oct 6 2014 08:43:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "N",
"path": "R4N",
"train_id": "9464",
"origin": null,
"destination": "Temple U",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 09:13:00:000PM",
"depart_time": "Oct 6 2014 09:13:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "N",
"path": "R4N",
"train_id": "466",
"origin": null,
"destination": "Warminster",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 09:43:00:000PM",
"depart_time": "Oct 6 2014 09:43:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "N",
"path": "R4N",
"train_id": "9468",
"origin": null,
"destination": "Temple U",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 10:13:00:000PM",
"depart_time": "Oct 6 2014 10:13:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "N",
"path": "R4N",
"train_id": "470",
"origin": null,
"destination": "Warminster",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 10:43:00:000PM",
"depart_time": "Oct 6 2014 10:43:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "N",
"path": "R4N",
"train_id": "9472",
"origin": null,
"destination": "Temple U",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 11:13:00:000PM",
"depart_time": "Oct 6 2014 11:13:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "N",
"path": "R4N",
"train_id": "474",
"origin": null,
"destination": "Warminster",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 11:43:00:000PM",
"depart_time": "Oct 6 2014 11:43:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "N",
"path": "R4N",
"train_id": "476",
"origin": null,
"destination": "Glenside",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 7 2014 12:13:00:000AM",
"depart_time": "Oct 7 2014 12:13:00:000AM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
}
]
},
{
"Southbound": [
{
"direction": "S",
"path": "R4S",
"train_id": "463",
"origin": "Warm",
"destination": "Airport",
"status": "On Time",
"service_type": "LOCAL",
"next_station": "30th Street Station",
"sched_time": "Oct 6 2014 08:49:00:000PM",
"depart_time": "Oct 6 2014 08:49:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "S",
"path": "R4S",
"train_id": "465",
"origin": "Warm",
"destination": "Airport",
"status": "1 min",
"service_type": "LOCAL",
"next_station": "Glenside",
"sched_time": "Oct 6 2014 09:19:00:000PM",
"depart_time": "Oct 6 2014 09:19:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "S",
"path": "R4S",
"train_id": "9467",
"origin": null,
"destination": "Airport",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 09:49:00:000PM",
"depart_time": "Oct 6 2014 09:49:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "S",
"path": "R4S",
"train_id": "469",
"origin": null,
"destination": "Airport",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 10:19:00:000PM",
"depart_time": "Oct 6 2014 10:19:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "S",
"path": "R4S",
"train_id": "9471",
"origin": null,
"destination": "Airport",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 10:49:00:000PM",
"depart_time": "Oct 6 2014 10:49:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "S",
"path": "R4S",
"train_id": "473",
"origin": null,
"destination": "Airport",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 11:19:00:000PM",
"depart_time": "Oct 6 2014 11:19:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
},
{
"direction": "S",
"path": "R4S",
"train_id": "9475",
"origin": null,
"destination": "Airport",
"status": "On Time",
"service_type": "LOCAL",
"next_station": null,
"sched_time": "Oct 6 2014 11:49:00:000PM",
"depart_time": "Oct 6 2014 11:49:00:000PM",
"track": "2",
"track_change": null,
"platform": " ",
"platform_change": null
}
]
}
]
}
如果更容易查看，您可以在http://www3.septa.org/hackathon/Arrivals/90404/10/查看JSON。 根节点似乎是动态的并带有时间戳。我想访问“Northbound”和“Southbound”节点中的信息。但是，我能够找到的每个示例都使用根节点并通过它访问子节点。由于这种情况下的根节点是自动生成并加上时间戳的，因此我不确定如何访问子节点。
我知道以下内容将正确返回'N'：
data['Airport Terminal A Departures: October 6, 2014, 8:31 pm'][0].Northbound[0].direction;
我确信我错过了一些明显的东西。非常感谢帮助。
答案 0 :(得分：1)
好的，您可以使用以下方法访问对象的密钥：
var json = ...; /* your json here */
for (var key in json) {
// Here the key variable will contain the key actual string, so...
var secondLevel = json[key]; // Here you're accessing the second-level object (an array [])
// Assuming the array only contains one Northbound and one Southbound parents...
var northbound_parent = secondLevel[0];
var southbound_parent = secondLevel[1];
// And now get the actual Northbound and Southbound arrays
var northbound = northbound_parent["Northbound"];
var southbound = southbound_parent["Southbound"];
// Here you have an array of objects...
for (var i = 0; i < northbound.length; i++) // Repeat for southbound
{
var nb_values = northbound[i]; // Object with properties
// Here you access them like nb_values["direction"]; and stuff
}
}
请注意，此代码可能会得到显着改进，但您需要了解它。
简答： 要使用您不知道的键访问值，您可以检查该特定对象内的所有键：
for (var key in object)
{
// key variable will contain the actual key (string, integer or whatever is being used), and each iteration will have one of the keys inside that object
}
答案 1 :(得分：1)
您可以尝试这样的事情：
var obj = JSON.parse(json);
var arr = obj[Object.keys(obj)];
var northbound = arr[0].Northbound;
var southbound = arr[1].Southbound;
此外，您可以使用for...in循环：
var obj = JSON.parse(json);
for(var i in obj) {
if(obj[i].length) var arr = obj[i];
}
现在arr是array，因此您可以loop或做类似的事情：
var northbound = arr[0].Northbound;
var southbound = arr[1].Southbound;
这只是一个抽象的想法。希望你能够完成剩下的工作： - ）