[英]How to convert a String that contains % into an Int in Swift
Here is the code:这是代码:
@IBAction func calculatePressed(_ sender: UIButton) {
let tip = tipPercentSelected.currentTitle ?? "unknown"
print(tip)
}
' tipPercentSelected ' here represents an amount of tips in % that can be chosen by the user, eg 20%.这里的' tipPercentSelected '表示可以由用户选择的以%为单位的提示量,例如20%。 In the code this ' tipPercentSelected ' if of type String.在代码中,这个“ tipPercentSelected ”如果是字符串类型。 I need to have 0.2 instead of 20% to be printed out to console when the relevant button is pressed.当按下相关按钮时,我需要将 0.2 而不是 20% 打印到控制台。 However, if ' tipPercentSelected ' is converted into Int it gives nil但是,如果将“ tipPercentSelected ”转换为 Int 它会给出nil
@IBAction func calculatePressed(_ sender: UIButton) {
let tip = tipPercentSelected.currentTitle ?? "unknown"
print(tip)
let tipConverted = Int(tip)
print(tipConverted)
}
What code do I need to get 0.2 instead of 20%?我需要什么代码才能获得 0.2 而不是 20%? Thanks.谢谢。
You should use a NumberFormatter
with style set to percent
您应该使用样式设置为percent
的NumberFormatter
let tipPercent = "20%"
let formatter = NumberFormatter()
formatter.numberStyle = .percent
if let tip = formatter.number(from: tipPercent) {
print(tip)
}
This prints 0.2这打印 0.2
In your view controller it could be something like this在你看来 controller 可能是这样的
static private let formatter: NumberFormatter = {
let formatter = NumberFormatter()
formatter.numberStyle = .percent
return formatter
}()
func calculatePressed(_ sender: UIButton) {
if let tip = tipPercentSelected.currentTitle, let tipConverted = Self.formatter.number(from: tip) {
print(tipConverted)
}
}
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