CODEWITHSUNDEEP
swift
Dan
Dan

Reputation: 830

Get next alphabet of a character

Is there any specific API to get the next alphabet of a character?

Example:

if "Somestring".characters.first results in "S", then should return "T"

If there's none I guess I have to iterate through a collection of alphabet and return the next character in order. Or is there any other better solution?

Upvotes: 3

Views: 4976

Answers (2)

Naveen Ramanathan
Naveen Ramanathan

Reputation: 2206

func nextChar(str:String) {
    if let firstChar = str.unicodeScalars.first {
        let nextUnicode = firstChar.value + 1
        if let var4 = UnicodeScalar(nextUnicode) {
            var nextString = ""
            nextString.append(Character(UnicodeScalar(var4)))
            print(nextString)
        }
    }
}
nextChar(str: "A")  // B
nextChar(str: "ΞΆ")  // Ξ·
nextChar(str: "z")  // {

Upvotes: 5

Martin R
Martin R

Reputation: 539795

If you think of the Latin capital letters "A" ... "Z" then the following should work:

func nextLetter(_ letter: String) -> String? {

    // Check if string is build from exactly one Unicode scalar:
    guard let uniCode = UnicodeScalar(letter) else {
        return nil
    }
    switch uniCode {
    case "A" ..< "Z":
        return String(UnicodeScalar(uniCode.value + 1)!)
    default:
        return nil
    }
}

It returns the next Latin capital letter if there is one, and nil otherwise. It works because the Latin capital letters have consecutive Unicode scalar values. (Note that UnicodeScalar(uniCode.value + 1)! cannot fail in that range.) The guard statement handles both multi-character strings and extended grapheme clusters (such as flags "πŸ‡©πŸ‡ͺ").

You can use 

    case "A" ..< "Z", "a" ..< "z":

if lowercase letters should be covered as well.

Examples:

nextLetter("B") // C
nextLetter("Z") // nil
nextLetter("€") // nil

Upvotes: 9

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