在分隔符中实现字符串Swift3

Question

我有一个问题。我使用货币工作，我想将正确的货币符号自动放入应用程序中以修剪整个字符串。首先，我有这样的代码剪断：

let firstPriceTrimmed = firstPrice.components(separatedBy: "€").flatMap { String($0.trimmingCharacters(in: .whitespaces)) }.last 

现在我的代码IST样子：

switch sideIDS { 
    case 6, 8, 9, 10, 12: 
     var current = "€" 
     let firstPriceTrimmedNew = firstPriceTrimmed?.components(separatedBy: String(current)) { String($0.trimmingCharacters(in: .whitespaces)) }.first 
    case 7: 
     var current = "£" 
     let firstPriceTrimmedNew = firstPriceTrimmed?.components(separatedBy: String(current)) { String($0.trimmingCharacters(in: .whitespaces)) }.last 
    case 11: 
     var current = "₹" 
     let firstPriceTrimmedNew = firstPriceTrimmed?.components(separatedBy: String(current)) { String($0.trimmingCharacters(in: .whitespaces)) }.last 
    default: 
     XCTFail() 
    } 

但没有奏效。 XCode将消息“Can not invoke'components'用类型为'（separatedBy：String ?,（_） - > _）'的参数列表'。'什么错误？我不明白XCode是什么意思...

Answer 1

你还没有加入.flapMap或switch所有cases内的任何其他封闭与components(separatedBy:)结果。

let firstPriceTrimmedNew: String 

switch sideIDS { 
case 6, 8, 9, 10, 12: 
    let current = "€" 
    firstPriceTrimmedNew = firstPriceTrimmed?.components(separatedBy: current).flatMap { String($0.trimmingCharacters(in: .whitespaces)) }.first 
case 7: 
    let current = "£" 
    firstPriceTrimmedNew = firstPriceTrimmed?.components(separatedBy: current).flatMap { String($0.trimmingCharacters(in: .whitespaces)) }.last 
case 11: 
    let current = "₹" 
    firstPriceTrimmedNew = firstPriceTrimmed?.components(separatedBy: current).flatMap { String($0.trimmingCharacters(in: .whitespaces)) }.last 
default: 
    XCTFail() 
}