I've trying to get a substring of a string starting from index 1 in iOS 10 beta 6, and its a headache as swifts strings are constantly changing and much documentation is out of date and useless.
String has the substring(from:Index), but it can't accept an integer (which has been the case for a while), so I was planning to use startIndex and advance it by 1, but now Index has no advanceBy method, so I cannot do this:
let aString = "hello"
let subString = aString.substring(from: aString.startIndex.advanceBy(1))
Looks pretty clear as the first item in the Swift 3 migration guide:
The most visible change is that indexes no longer have
distanceTo(_:)methods. Instead, those operations are moved to the collection, which is now responsible for incrementing and decrementing its indices.
myIndex.successor() => myCollection.index(after: myIndex) myIndex.predecessor() => myCollection.index(before: myIndex) myIndex.advance(by: …) => myCollection.index(myIndex, offsetBy: …)
So it looks like you want something like:
let greeting = "hello" let secondCharIndex = greeting.index(after: greeting.startIndex) let enryTheEighthGreeting = greeting.substring(from: secondCharIndex) // -> "ello"
(Note also that if you want
Collection functionality—like index management—on a
String, it sometimes helps to use its
String methods like
index(after:) are just conveniences that forward to the
characters view. That part isn't new, though...
Strings stopped being
Collections themselves in Swift 2 IIRC.)
There's more about the collection indexes change in SE-0065 - A New Model for Collections and Indices.