如何在Swift中将Unicode字符转换为Int

Question

A user asked the following question to one of my answers .

I have a unicode character \\u{0D85} . How do I get the Int value from it?

I was going to refer them to another Stack Overflow Q&A but I couldn't find one. These refer to converting the other direction:

• How to convert an Int to a Character in Swift
• How can I get the Unicode codepoint represented by an integer in Swift?

And these seem to be asking how to convert a number in string form to an actual Int (as in converting "1" to 1 ).

• Convert Character to Int in Swift 2.0
• Convert Character to Int in Swift

Rather than try to fit my answer in a comment to the asker, I am going to provide an answer below. The Type of \\u{0D85} is somewhat unclear but I will cover the various possibilities.

Answer 1

Hex to Int

If you are starting with \\u{0D85} and you know the hex value of the Unicode character, then you might as well write it in the following format because it is an Int already.

let myInt = 0x0D85                          // Int: 3461

String to Int

I assume, though, that you have "\\u{0D85}" (in quotes), which makes it a String by default. And since it is a String , you can't be certain that you will only have a single Int value for the general case.

let myString = "\u{0D85}"

for element in myString.unicodeScalars {
    let myInt = element.value               // UInt32: 3461
}

I could have also used myString.utf16 and let myInt = Int(element) , but I find it easier to deal with Unicode scalar values (UTF-32) when there is a possibility of things like emoji. (See this answer for more details.)

Character to Int

Swift Character , which is an extended grapheme cluster , does not have a utf16 or unicodeScalars property, so if you are starting with Character then convert it to a String first and then follow the directions in the String to Int section above.

let myChar: Character = "\u{0D85}"
let myString = String(myChar)

Answer 2

With Swift 5, Unicode.Scalar has a value property. value has the following declaration:

A numeric representation of the Unicode scalar.

var value: UInt32 { get }

---

The following Playground sample codes show how to iterate over the unicodeScalars property of a Character or a String and print the Int32 value of each Unicode scalar:

let char: Character = "\u{0D85}"

for scalar in char.unicodeScalars {
    print(scalar.value)
}

/*
 prints: 3461
 */

let str: String = "\u{0D85}"

for scalar in str.unicodeScalars {
    print(scalar.value)
}

/*
 prints: 3461
 */