Contents

init(validating:as:)

Creates a new string by copying and validating the sequence of code units passed in, according to the specified encoding.

Declaration

init?<Encoding>(validating codeUnits: some Sequence<Int8>, as encoding: Encoding.Type) where Encoding : _UnicodeEncoding, Encoding.CodeUnit == UInt8

Parameters

  • codeUnits:

    A sequence of code units that encode a String

  • encoding:

    A conformer to Unicode.Encoding that can decode codeUnits as UInt8

Discussion

This initializer does not try to repair ill-formed code unit sequences. If any are found, the result of the initializer is nil.

The following example calls this initializer with the contents of two different arrays—first with a well-formed UTF-8 code unit sequence and then with an ill-formed ASCII code unit sequence.

let validUTF8: [Int8] = [67, 97, 0, 102, -61, -87]
let valid = String(validating: validUTF8, as: UTF8.self)
print(valid ?? "nil")
// Prints "Café"

let invalidASCII: [Int8] = [67, 97, -5]
let invalid = String(validating: invalidASCII, as: Unicode.ASCII.self)
print(invalid ?? "nil")
// Prints "nil"

See Also

Creating a String from Unicode Data