Getting partial String in Swift5 [duplicate]

Question

I am trying to extract a partial String from a given input String in Swift5. Like the letters 2 to 5 of a String.

I was sure, something as simple as inputString[2...5]would be working, but I only got it working like this:

String(input[(input.index(input.startIndex, offsetBy: 2))..<(input.index(input.endIndex, offsetBy: -3))])

... which is still using relative positions (endIndex-3 instead of position #5)

Now I am wondering where exactly I messed up.

How do people usually extract "cde" from "abcdefgh" by absolute positions??

How about let input = "abcdefghij"; let cde = String(input.prefix(5).dropFirst(2))? — vacawama
– vacawama, Commented Jun 15, 2019 at 22:08

ThunderStruct · Accepted Answer · 2019-06-15 22:24:37Z

1

I wrote the following extension for shorthand substrings without having to deal with indexes and casting in my main code:

extension String {
    func substring(from: Int, to: Int) -> String {
        let start = index(startIndex, offsetBy: from)
        let end = index(start, offsetBy: to - from + 1)
        return String(self[start ..< end])
    }
}

let testString = "HelloWorld!"

print(testString.substring(from: 0, to: 4))     // 0 to 4 inclusive

Outputs Hello.

answered Jun 15, 2019 at 22:24

ThunderStruct

1,4926 gold badges23 silver badges32 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Leo Dabus Over a year ago

OP asked how to subscript the string with a range

ThunderStruct Over a year ago

Not really. OP asked for "something as simple as inputString[2...5]". Sure, it can be done by overloading the subscript operator, but this is a valid (arguably more readable) alternative solution.

Collectives™ on Stack Overflow

Getting partial String in Swift5 [duplicate]

1 Answer 1

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Linked

Related