Range issue in iOS

Question

I got an error message when I call the following method

pathString.removeSubrange(Range(pathString.startIndex..<pathString.index(pathString.startIndex, offsetBy: 7)))

Here is the error message

Cannot invoke initializer for type 'Range<_>' with an argument list of type '(Range)'

How would I change these statements to get rid of this error the transfer over to XCode 10 and Swift 4.2 is really giving me a hard time.

Looks like this

if pathString.contains("file://") {
    let startIndex = pathString.startIndex
    let endIndex = pathString.index(pathString.startIndex, offsetBy: 7)
    let range = startIndex..<endIndex
    pathString.removeSubrange(range)
}

Please don't hack your file url path. Learn the differences from absoluteString and path properties of a URL — Leo Dabus, Sep 20 '18 at 22:02
Show your actual problem. You shouldn't be working with strings (path) anymore. You should use only URL. if you have no alternative just check if the file:// prefix is present use `URL(string:)` initializer if the scheme it is not present use `URL(fileURLWithPath:)` initializer. — Leo Dabus, Sep 20 '18 at 22:13
This might help also https://stackoverflow.com/a/40643037/2303865 and https://stackoverflow.com/a/34135437/2303865 — Leo Dabus, Sep 20 '18 at 22:15

Yury Imashev · Accepted Answer · 2018-09-21T08:24:34.543

0

You don't need to call the Range initializer. Just do the following

pathString.removeSubrange(pathString.startIndex..<pathString.index(pathString.startIndex, offsetBy: 7))

or this, for more readability

let startIndex = pathString.startIndex
let endIndex = pathString.index(pathString.startIndex, offsetBy: 7)
let range = startIndex..<endIndex
pathString.removeSubrange(range)

UPDATE

In comments, Leo Dabus suggested the better solution

extension StringProtocol where Self: RangeReplaceableCollection {
    mutating func removePrefix(_ prefix: String) {
        if hasPrefix(prefix) {
            removeFirst(prefix.count)
        }
    }
}

After adding that you can simply call

pathString.removePrefix("file://")

edited Sep 21 '18 at 08:24

answered Sep 20 '18 at 21:45

Yury Imashev

2,068
1
18
32

umm i still get the same error even when i changed it – HiDungLing Sep 20 '18 at 21:51
Cannot invoke initializer for type 'Range<_>' with an argument list of type '(Range)' – HiDungLing Sep 20 '18 at 21:53
Are you sure that you've changed it in all cases? Because now you `range` has an appropriate type and the error should not occur. – Yury Imashev Sep 20 '18 at 21:54
@HiDungLing Yep. This error occurs for code from your question because you're calling `Range()` and get the range of the wrong type. For code from my answer, this error should not appear. – Yury Imashev Sep 20 '18 at 21:55
@HiDungLing That's weird. The updated code gives you the same error? Have you tried to rebuild your project? – Yury Imashev Sep 20 '18 at 21:58
yup and yes it does – HiDungLing Sep 20 '18 at 21:58
@HiDungLing Just to make sure, does `pathString` has a `String` type? – Yury Imashev Sep 20 '18 at 22:01
let me check bro – HiDungLing Sep 20 '18 at 22:04
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/180480/discussion-between-yury-imashev-and-hidungling). – Yury Imashev Sep 20 '18 at 22:04
1

This is a terrible approach. OP shouldn't be striping off the url scheme out of the string. Btw why not simply `str.dropFirst(7)` ??? – Leo Dabus Sep 20 '18 at 22:44
@LeoDabus Thank a lot for your comment! I update my answer with a better approach. – Yury Imashev Sep 20 '18 at 23:26
1

@YuryImashev better too extend StringProtocol and constrain it to RangeReplacebleCollection, then you can use mutating method removeFirst(n: Int). Note that extending StringProtocol instead of String you make the method available also for substrings – Leo Dabus Sep 21 '18 at 00:08
1

Your extension method should look like this `extension StringProtocol where Self: RangeReplaceableCollection { mutating func removePrefix(_ prefix: String) { if hasPrefix(prefix) { removeFirst(prefix.count) } } }` – Leo Dabus Sep 21 '18 at 00:09
But again OP shouldn't be striping off the url scheme from the absoluteString. – Leo Dabus Sep 21 '18 at 00:10
@LeoDabus Thanks for the suggestion! Answer updated. – Yury Imashev Sep 21 '18 at 08:25

score 0 · Answer 2 · answered Sep 20 '18 at 21:46

0

Hi there this looks like it's solved by this answer: https://stackoverflow.com/a/50719696/7932935

In your case replace:

pathString.removeSubrange(Range(pathString.startIndex..<pathString.index(pathString.startIndex, offsetBy: 7)))

with:

pathString.removeSubrange(pathString.startIndex..<pathString.index(pathString.startIndex, offsetBy: 7))

answered Sep 20 '18 at 21:46

Carlos S

26
5

I tested it on a Playground and it works for swift 4.2, like Yuri below is pathString a string? cheers! – Carlos S Sep 20 '18 at 22:18

Range issue in iOS

2 Answers2