String.Index does not have a member named advancedBy - swift

Question

I need to validate medicare number and I'm following this thread: How do I validate an Australian Medicare number?

I'm getting error as

Code is : String.Index does not have a member named advancedBy

 let matches = expression.matchesInString(medicareNumber, options: NSMatchingOptions.ReportProgress, range: NSMakeRange(0, length))


        if (matches.count > 0 && matches[0].numberOfRanges > 2) {
            let base = medicareNumber.substringWithRange(medicareNumber.startIndex...medicareNumber.startIndex.advancedBy(matches[0].rangeAtIndex(1).length))
            let checkDigitStartIndex = medicareNumber.startIndex.advancedBy(matches[0].rangeAtIndex(2).location )
            let checkDigitEndIndex = checkDigitStartIndex.advancedBy(matches[0].rangeAtIndex(2).length)
            let checkDigit = medicareNumber.substringWithRange(checkDigitStartIndex..<checkDigitEndIndex)
            var total = 0

            for i in 0..<multipliers.count {
                total += Int(base.charAtIndex(i))! * multipliers[i]
            }

            return (total % 10) == Int(checkDigit)
        }

I'm using Xcode 6.2 and how can I solve this issue? Please note I need to solve this without upgrade Xcode this moment.

Answer 1

Swift 1.2

Use advance

let base = medicareNumber.substringWithRange(
    medicareNumber.startIndex...advance(
        medicareNumber.startIndex,
        matches[0].rangeAtIndex(1).length
    )
)

Swift 2

advance has been deprecated in Swift2.
Use advanceBy

let base = medicareNumber.substringWithRange(
    medicareNumber.startIndex...medicareNumber.startIndex.advancedBy(
        matches[0].rangeAtIndex(1).length
    )
)

Swift 3

advancedBy(_:) has been deprecated in Swift3.
Use index(_:offsetBy:)

let base = medicareNumber.substringWithRange(
    medicareNumber.startIndex...medicareNumber.index(
        medicareNumber.startIndex,
        offsetBy: matches[0].rangeAtIndex(1).length)
    )
)