What is the replacement for isDigit() for characters in Swift?

Question

As mentioned in this post, before Xcode 6 Beta 4, one could use c.isDigit() and c.isAlpha() to find if c : Character was a digit or al

Answer 1

I have create mine var to check whether character is number or not.

var isNumber : Bool {
    get{
        return !self.isEmpty && self.rangeOfCharacter(from: CharacterSet.decimalDigits.inverted) == nil
    }
}

// Use

var initial = "1"
if let isNum = initial.isNumber, isNum { // true
    initial = "#"
} 

Answer 2

The "problem" is that a Swift character does not directly correspond to a Unicode code point, but represents an "extended grapheme cluster" which can consist of multiple Unicode scalars. For example

let c : Character = "                                                                    

                                                        
            

Answer 3

With Swift 5, according to your needs, you may choose one of the following ways in order to solve you problem.

---

#1. Using Character's isNumber property

Character has a property called isNumber. isNumber has the following declaration:

var isNumber: Bool { get }

A Boolean value indicating whether this character represents a number.

The Playground sample codes below show how to check if a character represents a number using isNumber:

let character: Character = "9"
print(character.isNumber) // true

let character: Character = "½"
print(character.isNumber) // true

let character: Character = "④"
print(character.isNumber) // true

let character: Character = "1⃣"
print(character.isNumber) // true

let character: Character = "1️⃣"
print(character.isNumber) // true

let character: Character = "৯"
print(character.isNumber) // true

let character: Character = "                                                                    

                                                        
            

Answer 4

About Swift 3:

According to the great Martin R answer's , for who have problems with the new swift:

replace:

let digits = NSCharacterSet.decimalDigitCharacterSet()

with:

let digits = NSCharacterSet.decimalDigits as NSCharacterSet

Answer 5

Swift 3 seems a little easier:

let str = "abcdef12345"
let digitSet = CharacterSet.decimalDigits

for ch in str.unicodeScalars {
    if digitSet.contains(ch) {
        // is digit!
    }
}

Answer 6

For a single character:

CharacterSet.decimalDigits.contains(string.unicodeScalars.first!)