Type 'String.Index' does not conform protocol '_Strideable'

Question

I read this thread but it seems have another problem. This code:

if value.range(of: String(formatter.minusSign))?.count > 0 {
    //STH
}

(where formatter is NumberFormatter object and value is String) produce this error in Swift:

Type 'String.Index' does not conform to protocol '_Strideable'

How to solve it?

What would the expected result for `count` be? What about a simple `if value.contains(formatter.minusSign)` ? — Martin R, Mar 06 '18 at 13:18
I am refactoring old objective-c code 1:1 and there was `if (!([value rangeOfString: [_formatter minusSign]].length > 0)){` — Piotr Wasilewicz, Mar 06 '18 at 13:37

vadian · Accepted Answer · 2018-03-06T13:22:40.030

1

You have to check if the range is not nil

if value.range(of: formatter.minusSign) != nil {
    //STH
}

or – preferable if you want to use the range – optional bindings

if let range = value.range(of: formatter.minusSign) {
    // do somthing with the range
}

or simply

if value.contains(formatter.minusSign) {
    //STH
}

edited Mar 06 '18 at 13:22

answered Mar 06 '18 at 13:15

vadian

`String(...)` isn't needed. – Martin R Mar 06 '18 at 13:21
@MartinR Right. *Don't adopt bad habits* – vadian Mar 06 '18 at 13:23
I have a range that the compiler tells me is not optional but I get that same error "Type 'String.Index' does not conform to protocol '_Strideable'". – David Rector May 30 '19 at 21:18

1 Answers1