我有一个小的快速应用程序，其中包括3个函数。
getIncData()，getExpData()（从firebase获取数据并将其存储在数组中）和getLeftBudget()，它应该从getIncData()计算数组的总值 - { {1}}
以下是我的代码的样子
getExpData()现在var income = [Double]()
var expenses = [Double]()
var totalIncome: Double = 0
var totalExpenses: Double = 0
func getIncData() {
let budgetDB = Database.database().reference().child("Income")
budgetDB.observe(.childAdded) { (snapshot) in
let snapshotValue = snapshot.value as! Dictionary<String, String>
let value = snapshotValue["Value"]!
self.income.append(Double(Int(value)!))
self.totalIncome = self.income.reduce(0, +)
self.incomeLabel.text = "Income: " + String(self.totalIncome) + " €";
}
}
func getExpData() {
let budgetDB = Database.database().reference().child("Expenses")
budgetDB.observe(.childAdded) { (snapshot) in
let snapshotValue = snapshot.value as! Dictionary<String, String>
let value = snapshotValue["Value"]!
self.expenses.append(Double(value)!)
self.totalExpenses = self.expenses.reduce(0, +)
self.expensesLabel.text = "Expenses: " + String(Double(self.totalExpenses)) + " €";
}
func getLeftBudget() {
let budgetLeft = self.totalIncome - self.totalExpenses
self.budgetMonth.text = "Budget left - \(String(budgetLeft))"
}
内的self.totalIncome和self.totalExpenses返回0.什么是将函数数据转换为第三个函数以便进行计算的最佳方法？
P.S。数组将填充来自firebase的数据，计算在getLeftBudget和getIncData()