字符串转换为Int并将逗号替换为加号

Question

使用Swift,我试图在应用程序的文本视图中输入一个数字列表,并通过提取成绩计算器的每个数字来创建此列表的总和.此外,用户输入的值的数量也会发生变化.一个例子如下所示:

字符串:98,99,97,96 ...试图得到:98 + 99 + 97 + 96 ......

请帮忙!谢谢

Answer 1

1. 使用components(separatedBy:)打破了逗号分隔的字符串.
2. 使用trimmingCharacters(in:)前,每一个元素后删除空格
3. 使用Int()每个元素转换为整数.
4. 使用compactMap(以前称为flatMap)删除任何无法转换的项目Int.

5. 使用reduce总结的阵列Int.

   let input = " 98 ,99 , 97, 96 "
   
   let values = input.components(separatedBy: ",").compactMap { Int($0.trimmingCharacters(in: .whitespaces)) }
   let sum = values.reduce(0, +)
   print(sum)  // 390
   

Answer 2

对于Swift 3和Swift 4.

简单方法:硬编码.仅在您知道正在出现的整数的确切数量时才有用,希望进一步计算和打印/使用.

let string98: String = "98"
let string99: String = "99"
let string100: String = "100"
let string101: String = "101"

let int98: Int = Int(string98)!
let int99: Int = Int(string99)!
let int100: Int = Int(string100)!
let int101: Int = Int(string101)!

// optional chaining (if or guard) instead of "!" recommended. therefore option b is better

let finalInt: Int = int98 + int99 + int100 + int101

print(finalInt) // prints Optional(398) (optional)

作为一种功能的奇特方式:通用方式.在这里,您可以根据需要添加尽可能多的字符串.例如,您可以先收集所有字符串,然后使用数组计算它们.

func getCalculatedIntegerFrom(strings: [String]) -> Int {

    var result = Int()

    for element in strings {

        guard let int = Int(element) else {
            break // or return nil
            // break instead of return, returns Integer of all 
            // the values it was able to turn into Integer
            // so even if there is a String f.e. "123S", it would
            // still return an Integer instead of nil
            // if you want to use return, you have to set "-> Int?" as optional
        }

        result = result + int

    }

    return result

}

let arrayOfStrings = ["98", "99", "100", "101"]

let result = getCalculatedIntegerFrom(strings: arrayOfStrings)

print(result) // prints 398 (non-optional)

Answer 3

let myString = "556" let myInt = Int(myString)