iOS Parsing text file Swift - ios

Question

I try to parse my txt file, i have question and 5 answers in txt file, and i want to save question to separate variable, and similar answers.
My code:
do {
let path = Bundle.main.path(forResource: "data", ofType: "txt")
let source = try? String.init(contentsOfFile: path!)
var elements = source?.components(separatedBy: "\n")
var parsedObject = [[String: String]]()
for i in 0..<(elements?.count)! - 1 {
let objects = [String : String]()
let element = elements![i]
//print(element)
let objectsElement = element.components(separatedBy: "\r")
let question = objectsElement[0]
let answer1 = objectsElement[1]
let answer2 = objectsElement[2]
let answer3 = objectsElement[3]
let anserr4 = objectsElement[4]
let answer5 = objectsElement[5]
print(question, answer1, answer2, answer3, anserr4, answer5)
print(objectsElement)
}
}
Error which i received:
Thread 1: Fatal error: Index out of range
If i comment this code:
let question = objectsElement[0]
let answer1 = objectsElement[1]
let answer2 = objectsElement[2]
let answer3 = objectsElement[3]
let anserr4 = objectsElement[4]
let answer5 = objectsElement[5]
print(question, answer1, answer2, answer3, anserr4, answer5)
I will get such output:
Structure file:
https://drive.google.com/file/d/1ah1Mk_WY3b_qbqKM18nxxPT1rNXFiISa/view?usp=sharing

Answer 1

Parsing a text file is very, very tedious.
Here is a quick&dirty converter from your .txt file to JSON using regular expression.
The JSON dictionaries have the format
question (String), the question text
answers([String]), an array of answers
correctAnswerIndex (Int), the zero-based index of the correct answer in answers
number (Int), the question number.
The regex pattern searches for
one or more digits or one letter in range A...E (is captured) - (\\d+|[A-E])
followed by a dot and a whitespace character - \\.\\s
followed by one or more arbitrary characters (is captured) - (.+)
let url = Bundle.main.url(forResource: "data", withExtension: "txt")!
let string = try! String(contentsOf: url, encoding: .utf8)
let pattern = "(\\d+|[A-E])\\.\\s(.+)"
let regex = try! NSRegularExpression(pattern: pattern)
var result = [[String:Any]]()
var question = [String:Any]()
var answers = [String]()
var answerCounter = 0
let matches = regex.matches(in: string, range: NSRange(string.startIndex..<string.endIndex, in: string))
for match in matches {
let index = string[Range(match.range(at: 1), in: string)!]
var text = string[Range(match.range(at: 2), in: string)!]
if let ordinal = Int(index) {
question["number"] = ordinal
question["question"] = text
} else {
if text.hasPrefix("*") {
text = text.dropFirst()
question["correctAnswerIndex"] = answerCounter
}
answers.append(String(text))
answerCounter += 1
if answerCounter == 5 {
question["answers"] = answers
result.append(question)
question = [:]
answers = []
answerCounter = 0
}
}
}
let jsonData = try! JSONSerialization.data(withJSONObject: result)
let jsonString = String(data: jsonData, encoding: .utf8)!
print(jsonString)
Save that JSON in the bundle as data.json and delete the text file
Now you can decode the JSON into a struct with
struct Question : Decodable {
let question : String
let answers : [String]
let correctAnswerIndex : Int
let number : Int
}
let url = Bundle.main.url(forResource: "data", withExtension: "json")!
let data = try! Data(contentsOf: url)
do {
let result = try JSONDecoder().decode([Question].self, from: data)
print(result)
} catch {
print(error)
}

Answer 2

Have a look a your txt file by printing source. You'll get something like this:
Optional("1. A patient with ischemic heart disease has been administered inosine which is an intermediate metabolite in the synthesis of:\n A. Metalloproteins\n B. Glycoproteins\n C. Ketone bodies\n D. *Purine nucleotides\n E. Lipoproteins\n\n2. Rates of chemical reactions of the same order are compared by:\n A. *Constant of chemical reaction rate\n B. Endpoint of a reaction\n C. Change in the concentration of the reaction products\n D. Change in the reactants concentration\n E. Chemical reaction rate\n\n ...etc)
As you can see, Questions are separated by \n\n
var elements = source?.components(separatedBy: "\n\n")
Then you can separate the question and its answers by \n
let objectsElement = element.components(separatedBy: "\n")
Make sure in your txt file that Questions are separated by two newlines, and that question have only one new line between them.

Answer 3

In your case one way to achieve what you want is this:
do {
let path = Bundle.main.path(forResource: "Data", ofType: "txt")
let source = try? String.init(contentsOfFile: path!)
var elements = source?.components(separatedBy: "\n\n") // Here is the change
var parsedObject = [[String: String]]()
for i in 0..<(elements?.count)! - 1 {
let objects = [String : String]()
let element = elements![i]
let objectsElement = element.components(separatedBy: "\n") // And Here
if objectsElement.count > 1 {
let question = objectsElement[0]
let answer1 = objectsElement[1]
let answer2 = objectsElement[2]
let answer3 = objectsElement[3]
let answer4 = objectsElement[4]
let answer5 = objectsElement[5]
print("Question: \(question)")
print("Answer: \(answer1)")
print("Answer: \(answer2)")
print("Answer: \(answer3)")
print("Answer: \(answer4)")
print("Answer: \(answer5)")
}
}
}
If you are not changing your text file format then in this way you can get the solution. For now you can try this solution but search for better one or if I will get one I will post the answer soon.

Answer 4

You are trying to access elements in the location 0 to 5 of the array objectsElement. So whenever the objectsElement.count < 6 its going to throw Thread 1: Fatal error: Index out of range
Seeing your output i think every time objectsElement has only one element in it.