Swift 4 - 'substring(to:)' is deprecated - Alternative To My Code

Question

My code was as below

   var theReview = addReview.text
    let len2 = addReview.text.utf16.count

    if len2 > 3000 {

        theReview = theReview?.substring(to: (theReview?.index((theReview?.startIndex)!, offsetBy: 3000))!)

    }

My aim was to get the first 3000 characters of the text if it is longer than 3000 characters.

However, I get the warning below:

'substring(to:)' is deprecated: Please use String slicing subscript with a 'partial range upto' operator

What can be an alternative to my code. I am not a very professional coder. So any help would be great.

score 5 · Accepted Answer · answered Jun 11 '19 at 11:26

Simply call prefix(_:) on theReview with the required length.

func prefix(_ maxLength: Int) -> Substring

Returns a subsequence, up to the specified maximum length, containing the initial elements of the collection.

If the maximum length exceeds the number of elements in the collection, the result contains all the elements in the collection

var theReview = addReview.text
theReview = String(theReview.prefix(3000))

Note: There is no need to check if the theReview's length exceeds 3000. It will be handled by prefix(_:) itself.

I guess this could even be compressed to `let theReview = String(addReview.text.prefix(3000))` — Joakim Danielson, Jun 11 '19 at 11:39

Naqeeb · Answer 2 · 2019-06-11T12:40:26.293

1

might this could help you

var theReview = addReview.text
theReview = String(theReview.prefix(3000))

edited Jun 11 '19 at 12:40

answered Jun 11 '19 at 11:28

Naqeeb

1,121
8
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See the answer by PGDev for a better use of `prefix()` – Joakim Danielson Jun 11 '19 at 11:37
@JoakimDanielson yes i saw PGDev answer , better one – Naqeeb Jun 11 '19 at 11:41
Even if string length under 3000 `.prefix` will still work. – user28434'mstep Jun 11 '19 at 11:54
@user28434 yes thats why we embed it in an if condition – Naqeeb Jun 11 '19 at 12:38
@NaqeebAhmed, I mean `if` is not needed, in worst case you gonna get original string. – user28434'mstep Jun 11 '19 at 12:39

score 0 · Answer 3 · answered Jun 11 '19 at 11:33

0

Use String init with slice.

let index = theReview.index(theReview.startIndex, offsetBy: 3000)
theReview = String(theReview[theReview.startIndex..<index])

or prefix as mentioned in previous answers

answered Jun 11 '19 at 11:33

Kirow

1,077
12
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@JoakimDanielson sure thing. but length check present in question. – Kirow Jun 11 '19 at 11:40

Swift 4 - 'substring(to:)' is deprecated - Alternative To My Code

3 Answers3