我的数据库中有以下格式的数据（这些数据块中至少有100,000个）：
{
"ax" : 1.232,
"ay" : 1.897,
"az" : -0.232
"timestamp" : 151232326789
}
我要在我的iOS应用程序中以字典的格式检索并解析为类模型。
上面的数据来自传感器MPU6050，与Firebase使用的NodeMCU通信。由于NodeMCU没有自己的时钟，因此使用ServerValue.Timestamp为数据提供时间戳是唯一的选择。因此，我无法正确构造我现在需要在iOS应用程序上格式化的JSON数据。
我正在从数据库中的时间戳记中提取time和date
这是我在前端中需要的格式：
{
Date1 : {
Time1 :{
"ax" : 1.232,
"ay" : 1.897,
"az" : -0.232
},
Time2 :{
"ax" : 1.232,
"ay" : 1.897,
"az" : -0.232
},
Time3 :{
"ax" : 1.232,
"ay" : 1.897,
"az" : -0.232
},
Time4 :{
"ax" : 1.232,
"ay" : 1.897,
"az" : -0.232
}
}
Date2 : {...similar as above.}
}
我尝试使用NSMutableDictionary，但是数据混乱了。有解决方案吗？
答案 0 :(得分：1)
我将其构造为一个实体，该实体在数组中保存一个日期的传感器数据，并由于字典未排序而在数组中存储该实体的实例。
var allData: [OneDayData]
struct OneDayData {
var date: Date
var sensorData: [SensorData]
}
struct SensorData {
var time: String
var ax: Double
var ay: Double
var az: Double
}
注意，我不知道您如何转换时间戳，因此我只是假设它已转换为日期和字符串
答案 1 :(得分：1)
import Foundation
// define date - time interval for testing
let start = Calendar.current.date(from: DateComponents(year: 2018, month: 1, day: 1))
let end = Calendar.current.date(from: DateComponents(year: 2018, month: 1, day: 3))
let s = start!.timeIntervalSinceReferenceDate
let e = end!.timeIntervalSinceReferenceDate
// generate array of random data with timestamp from defined date - time interval
var data: [[String: Double]] = []
(0..<10).forEach { _ in
let ax = Double.random(in: -1.0...1.0)
let ay = Double.random(in: -1.0...1.0)
let az = Double.random(in: -1.0...1.0)
// stamp between start and end date, with one second resolution
let timestamp = TimeInterval.random(in: s...e).rounded()
let record = ["ax": ax, "ay": ay, "az": az, "timestamp": timestamp]
data.append(record)
}
print(data as NSArray)有什么用？
(
{
ax = "-0.9915295335923959";
ay = "0.04220588780831558";
az = "0.04947324263041164";
timestamp = 536480749;
},
{
ax = "0.8339518841345668";
ay = "-0.8796254984325194";
az = "0.9274526027609205";
timestamp = 536596358;
},
{
ax = "0.1892933660394962";
ay = "0.2786212981444189";
az = "-0.7010853895168836";
timestamp = 536453459;
},
{
ax = "-0.3879536539762585";
ay = "-0.9881198368284949";
az = "-0.8103733151058379";
timestamp = 536574669;
},
{
ax = "0.4386373099712233";
ay = "-0.1082200532953461";
az = "-0.5452489312143274";
timestamp = 536515655;
},
{
ax = "0.1021774847462089";
ay = "-0.6414676993950421";
az = "0.8826716373674426";
timestamp = 536455164;
},
{
ax = "0.1877861732407253";
ay = "-0.6069605631703257";
az = "-0.3766270018644693";
timestamp = 536569833;
},
{
ax = "0.3011539934614316";
ay = "-0.8534914632655413";
az = "0.652288374381045";
timestamp = 536477646;
},
{
ax = "-0.3087207248856481";
ay = "0.566261641115348";
az = "-0.6320769324182691";
timestamp = 536563296;
},
{
ax = "-0.5450288945879682";
ay = "0.6143645223909975";
az = "-0.8973854689667276";
timestamp = 536609836;
}
)
现在，我收到的数据与您收到的格式相同（不是JSON，而是Swift的字典数组），并且有了下一个简单功能的帮助
// extract date and time from timestamp value
func stamp(timestamp: TimeInterval)->(date: String, time: String) {
let date = Date(timeIntervalSinceReferenceDate: timestamp)
return (DateFormatter.localizedString(from: date, dateStyle: .short, timeStyle: .none),
DateFormatter.localizedString(from: date, dateStyle: .none, timeStyle: .medium))
}
我们准备根据需要按日期和时间对数据值进行分组
// group data by date and time, if duplicated timestamp, use last value only
let result = data.reduce(into: [String:[String:[String: Double]]]()) { (result, record) in
guard let ts = record["timestamp"] else { return }
var record = record
record["timestamp"] = nil
let (date, time) = stamp(timestamp: ts)
if result[date] == nil {
result[date] = [time : record]
} else {
result[date]?[time] = record
}
}
查看结果[String:[String:[String: Double]]]显示为NSDictionary的样子
{
"01/01/2018" = {
"00:50:59" = {
ax = "0.1892933660394962";
ay = "0.2786212981444189";
az = "-0.7010853895168836";
};
"01:19:24" = {
ax = "0.1021774847462089";
ay = "-0.6414676993950421";
az = "0.8826716373674426";
};
"07:34:06" = {
ax = "0.3011539934614316";
ay = "-0.8534914632655413";
az = "0.652288374381045";
};
"08:25:49" = {
ax = "-0.9915295335923959";
ay = "0.04220588780831558";
az = "0.04947324263041164";
};
"18:07:35" = {
ax = "0.4386373099712233";
ay = "-0.1082200532953461";
az = "-0.5452489312143274";
};
};
"02/01/2018" = {
"07:21:36" = {
ax = "-0.3087207248856481";
ay = "0.566261641115348";
az = "-0.6320769324182691";
};
"09:10:33" = {
ax = "0.1877861732407253";
ay = "-0.6069605631703257";
az = "-0.3766270018644693";
};
"10:31:09" = {
ax = "-0.3879536539762585";
ay = "-0.9881198368284949";
az = "-0.8103733151058379";
};
"16:32:38" = {
ax = "0.8339518841345668";
ay = "-0.8796254984325194";
az = "0.9274526027609205";
};
"20:17:16" = {
ax = "-0.5450288945879682";
ay = "0.6143645223909975";
az = "-0.8973854689667276";
};
};
}
JSON部分由您决定。
答案 2 :(得分：0)
字典无法解决您的问题。这里需要的是自定义模型的数组。
例如，
struct Time {
var ax: Float
var ay: Float
var az: Float
}
struct Date {
var times: [Time]
}
let array: [Date] = ... // parse your json into this
您需要将json的解析逻辑写入此结构，该逻辑可以通过多种方式完成，而且我认为这超出了最初的问题范围
答案 3 :(得分：0)
jsonResponse是您的数组
if let dictionary = jsonResponse as? [String : Any]
{
let all=dictionary["Date1"] as? [[String : Any]]
if let all = all
{
let user:[String:Any]=all[0]["Time1"]! as! [String : Any]
let user2:[String:Any]=all[0]["Time2"]! as! [String : Any]
print(user["ax"] as? String)!,user["ay"] as? String)!,user["az"] as? String)!)
print(user2["ax"] as? String)!,user2["ay"] as? String)!,user2["az"] as? String)!)
}
}