Interested in learning how to extract an array from a description in Swift 4?

Question

Interested in learning how to extract an array from a description in Swift 4?

Currently delving into Swift 4, I've come across an algorithm that generates the base 64 representation of an array, as shown below:

extension String {

    func fromBase64() -> String? {
        guard let data = Data(base64Encoded: self) else {
            return nil
        }

        return String(data: data, encoding: .utf8)
    }

    func toBase64() -> String {
        return Data(self.utf8).base64EncodedString()
    }
}
let output = [1, 2, 4, 65].description.toBase64()
print(output.fromBase64()) // "[1, 2, 4, 65]"

The challenge now lies in extracting the array back as an Array, rather than a String. Despite my efforts in researching online resources, parsing methods for this particular type of array have proven elusive (most discussions revolve around JSON parsing).

ios arrays json swift parsing

Answer 1

Answer №1

It is not recommended to depend on the description method for generating a specific output consistently; it is advisable to use a JSON encoder instead (as demonstrated below).

However, it should be noted that "[1, 2, 4, 65]" is a valid JSON array, and a JSON decoder can successfully parse it into an integer array:

let output = "[1, 2, 4, 65]"
do {
    let array = try JSONDecoder().decode([Int].self, from: Data(output.utf8))
    print(array) // [1, 2, 4, 65]
} catch {
    print("Invalid input", error.localizedDescription)
}

Below is a comprehensive example illustrating how you can accurately encode and decode an array of integers to/from a Base64 encoded string.

// Encoding:
let intArray = [1, 2, 4, 65]
let output = try! JSONEncoder().encode(intArray).base64EncodedString()
print(output) // WzEsMiw0LDY1XQ==

// Decoding:
let output = "WzEsMiw0LDY1XQ=="
if let data = Data(base64Encoded: output),
    let array = try? JSONDecoder().decode([Int].self, from: data) {
    print(array) // [1, 2, 4, 65]
} else {
    print("Invalid input")
}

Answer 2

It is not recommended to depend on the description method for generating a specific output consistently; it is advisable to use a JSON encoder instead (as demonstrated below).

However, it should be noted that "[1, 2, 4, 65]" is a valid JSON array, and a JSON decoder can successfully parse it into an integer array:

let output = "[1, 2, 4, 65]"
do {
    let array = try JSONDecoder().decode([Int].self, from: Data(output.utf8))
    print(array) // [1, 2, 4, 65]
} catch {
    print("Invalid input", error.localizedDescription)
}

Below is a comprehensive example illustrating how you can accurately encode and decode an array of integers to/from a Base64 encoded string.

// Encoding:
let intArray = [1, 2, 4, 65]
let output = try! JSONEncoder().encode(intArray).base64EncodedString()
print(output) // WzEsMiw0LDY1XQ==

// Decoding:
let output = "WzEsMiw0LDY1XQ=="
if let data = Data(base64Encoded: output),
    let array = try? JSONDecoder().decode([Int].self, from: data) {
    print(array) // [1, 2, 4, 65]
} else {
    print("Invalid input")
}

Answer 3

Answer №2

If you're looking to transform a string into an array of integers, consider using the following method:

let encodedString = original.encodeBase64() //"[8, 14, 36, 92]"
if let str = encodedString {
    let charactersToStrip = CharacterSet(charactersIn: ",][ ")
    let separatedValues = str.components(separatedBy: charactersToStrip).filter { $0 != "" }.flatMap { Int($0)}
    print(separatedValues) //[8, 14, 36, 92]
}

Answer 4

If you're looking to transform a string into an array of integers, consider using the following method:

let encodedString = original.encodeBase64() //"[8, 14, 36, 92]"
if let str = encodedString {
    let charactersToStrip = CharacterSet(charactersIn: ",][ ")
    let separatedValues = str.components(separatedBy: charactersToStrip).filter { $0 != "" }.flatMap { Int($0)}
    print(separatedValues) //[8, 14, 36, 92]
}

Interested in learning how to extract an array from a description in Swift 4?

Answer №1

Answer №2

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