Swift 4 'substring(from:)' is deprecated: Please use String slicing subscript with a 'partial range from' operator - swift

Question

i've just converted my little app but i've found this error:
'substring(from:)' is deprecated: Please use String slicing subscript with a 'partial range from' operator
my code is:
let dateObj = dateFormatterFrom.date(from: dateStringa)
if dateObj != nil {
cell.detailTextLabel?.text = dateFormatterTo.string(from:(dateObj!))
} else {
let index = thisRecord.pubDate.index(thisRecord.pubDate.startIndex, offsetBy: 5)
cell.detailTextLabel?.text = thisRecord.pubDate.substring(from: index)
}

Answer 1

Follow the below example to fix this warning:
Supporting examples for Swift 3, 4 and 5.
let testStr = “Test Teja”
let finalStr = testStr.substring(to: index) // Swift 3
let finalStr = String(testStr[..<index]) // Swift 4
let finalStr = testStr.substring(from: index) // Swift 3
let finalStr = String(testStr[index...]) // Swift 4
//Swift 3
let finalStr = testStr.substring(from: index(startIndex, offsetBy: 3))
//Swift 4 and 5
let reqIndex = testStr.index(testStr.startIndex, offsetBy: 3)
let finalStr = String(testStr[..<reqIndex])
//**Swift 5.1.3 - usage of index**
let myStr = "Test Teja == iOS"
let startBound1 = String.Index(utf16Offset: 13, in: myStr)
let finalStr1 = String(myStr[startBound1...])// "iOS"
let startBound2 = String.Index(utf16Offset: 5, in: myStr)
let finalStr2 = String(myStr[startBound2..<myStr.endIndex]) //"Teja == iOS"

Answer 2

In place of substring use suffix. Use like below :
cell.detailTextLabel?.text = String(thisRecord.pubDate.suffix(from: index))

Answer 3

It means you should use the new partial range operator as your upperBound:
let str = "Hello World !!!"
if let index = str.range(of: "Hello ")?.upperBound {
let string = String(str[index...]) // "World !!!"
}
In your case
cell.detailTextLabel?.text = String(thisRecord.pubDate[index...]))

Answer 4

In Swift 5, it is:
extension String {
func index(from: Int) -> Index {
return self.index(startIndex, offsetBy: from)
}
func substring(from: Int) -> String {
let fromIndex = index(from: from)
return String(self[fromIndex...])
}
func substring(to: Int) -> String {
let toIndex = index(from: to)
return String(self[..<toIndex])
}
func substring(with r: Range<Int>) -> String {
let startIndex = index(from: r.lowerBound)
let endIndex = index(from: r.upperBound)
return String(self[startIndex..<endIndex])
}
}

Answer 5

Most of my strings have A-Za-z and 0-9 content. No need for difficult
Index handling. This extension of String is based on the familiar LEFT / MID and RIGHT functions.
extension String {
// LEFT
// Returns the specified number of chars from the left of the string
// let str = "Hello"
// print(str.left(3)) // Hel
func left(_ to: Int) -> String {
return "\(self[..<self.index(startIndex, offsetBy: to)])"
}
// RIGHT
// Returns the specified number of chars from the right of the string
// let str = "Hello"
// print(str.left(3)) // llo
func right(_ from: Int) -> String {
return "\(self[self.index(startIndex, offsetBy: self.length-from)...])"
}
// MID
// Returns the specified number of chars from the startpoint of the string
// let str = "Hello"
// print(str.left(2,amount: 2)) // ll
func mid(_ from: Int, amount: Int) -> String {
let x = "\(self[self.index(startIndex, offsetBy: from)...])"
return x.left(amount)
}
}

Answer 6

If you wish to get substring with specific offset without upper bound do the following:
let index = thisRecord.pubDate.index(thisRecord.pubDate.startIndex, offsetBy: 5)
cell.detailTextLabel?.text = String(thisRecord.pubDate[index...]
This way you create a new String object from your existing String thisRecord.pubDate taking anything from specified index to the end index of original String.

Answer 7

str[..<index]
str[index...]
The code above is "partial range from"
Look at this How can I use String slicing subscripts in Swift 4?