CODEWITHSUNDEEP
iosswift
user3395936
user3395936

Reputation: 681

fatal error: Array index out of range Swift

In this example, I am creating a new empty array of Int and I want to add certain characters from the other array into it. Originally, in my characters array I store numbers ["1","","2","","3"] and in this array (I might be doing this completely wrong) I want to iterate through those numbers to produce a newarray which will have these numbers [1,2,3] (essentially removing the spaces in between and making them of type Int)

As far as I understand, I have created a dynamic array i.e. no specific size, but I am getting this error : fatal error: Array index out of range and I am not sure why. Could someone clarify this for me? Thanks

 do{
        var data = try String(contentsOfFile: documentsDirectoryPath as String,
            encoding: NSASCIIStringEncoding)
        print(data)
        let characters = Array(data.characters)
        print(characters)
        var newarray = [Int]()

        for var index = 0; index <= characters.count ; ++index {
            if characters[index] == " " {
                index++
            }
            else{
                newarray[index] = index
            }
        }
        print(newarray)    
    }
    catch{

        print("error")
    }   
}

Upvotes: 0

Views: 2223

Answers (6)

Slayter
Slayter

Reputation: 1170

Seeing from your other comments in this thread it appears you are trying to filter out spaces and commas from a string that may look like "1, 2, 3". Correct me if this is wrong. The completely swifty solution to this is as follows:

do {
    var data = try String(contentsOfFile: documentsDirectoryPath as String, encoding: NSASCIIStringEncoding)
    print(data)

    let newarray = data.characters.filter { Int(String($0)) != nil }.map { Int(String($0))! }    
} catch {
    print("error")
}

Explanation

filter will return an array of Characters that convert to integers. map will then take that array and then transform each element into an integer. We have to convert the Character to a String type because there is no Int constructor that takes a Character.

Upvotes: 2

Wajih
Wajih

Reputation: 4393

change this line:

for var index = 0; index <= characters.count ; ++index {

to this one:

for var index = 0; index < characters.count ; ++index {

Upvotes: 0

koen
koen

Reputation: 5741

Another approach:

First remove all spaces from the String, then convert it to Array:

let trimmedData = data.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
let characters = Array(trimmedData.characters)

Edit: if you just want to keep the numbers:

let validNumbers = "1234567890"
let validSet = NSCharacterSet(charactersInString: validNumbers)
let trimmedData = data.stringByTrimmingCharactersInSet(validSet)
let characters = Array(trimmedData.characters)

Upvotes: 0

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 727047

You have several issues in your code, most important of which is that your approach is incorrect, because it treats a string as a collection of individual characters, while your problem calls for parsing multi-digit numbers.

A better approach is to split the array on commas, and parse integers from trimmed results, like this:

let data = "12, 23, 345"
print(data)
let newarray = data.characters.split(){$0 == ","}.map{
    Int(String.init($0).stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet()))!
}
print(newarray) // 12, 23, 345

Upvotes: 1

s1ddok
s1ddok

Reputation: 4654

Based on what you told in comments (you want to remove space chars from array and get the new one), you can achieve it like so:

let newarray = characters.filter { $0 != " " }

Upvotes: 0

s1ddok
s1ddok

Reputation: 4654

This happens because your newarray has no capacity.

Try using append method or create array with capacity like so:

let newarray = [Int](count:charactes.count, repeatedValue: 0).

P.S. Also note that you have mistake in for loop, you should use <instead of <= and hustling with iterator value within the loop is a bad idea, you increment this var twice when you see a space, are you sure that is intended?

And you are using two bad practices in Swift. First of all, you use C-like for-loop which will be removed in Swift 3. Same goes for ++ operators. They will be removed too.

Use for-in and += instead. This will make your code more Swift-ish.

Upvotes: 0

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