如何将字符串的每个备用字符大写？

Question

假设有一个字符串 "johngoestoschool" 它应该变成 "JoHnGoEsToScHoOl" 并且如果中间有一个特殊字符它应该忽略它例如 given string "jo$%@#hn^goe!st#os&choo)l" 答案应该是 "Jo$%@#Hn^GoE!sT#oS&cHoO)l"

根据的回答，为了迭代我们可以这样做：

let s = "alpha"
for i in s.characters.indices[s.startIndex..<s.endIndex]
{
    print(s[i])
}

为什么我们不能在这里打印 "i" 的值？当我们执行 i.customPlaygroundQuickLook 时，它会键入 int 0 到 int4。

所以我的想法是

if (i.customPlaygroundQuickLook == 3) {
        s.characters.currentindex = capitalized
}

请帮忙

Answer 1

这应该可以解决您的功能，困难的部分只是检查天气字符是否为字母，使用 inout 并替换范围会提供更好的性能：

func altCaptalized(string: String) -> String {
    var stringAr = string.characters.map({ String([=10=]) }) // Convert string to characters array and mapped it to become array of single letter strings
    var numOfLetters = 0

    // Convert string to array of unicode scalar character to compare in CharacterSet
    for (i,uni) in string.unicodeScalars.enumerated() {
        //Check if the scalar character is in letter character set
        if CharacterSet.letters.contains(uni) { 
            if numOfLetters % 2 == 0 {
                stringAr[i] = stringAr[i].uppercased() //Replace lowercased letter with uppercased
            }
            numOfLetters += 1
        }
    }

    return stringAr.joined() //Combine all the single letter strings in the array into one string
}

如何将字符串的每个备用字符大写？

How to capitalize each alternate character of a string?

arrays

string

ios

swift-playground

swift3