Swift 4: Cannot subscript a value of type 'String' with an index of type 'CountablePartialRangeFrom<Int>'

Question

So I have this Swift code:

func didReceiveResponse(response:String) {
  ...
  let substr = response[11...]

By my interpretation, substr should be a Substring referencing all characters after index 11 in the response string.

What actually happens is this compiler error:

Cannot subscript a value of type 'String' with an index of type 'CountablePartialRangeFrom<Int>'

This seems like it should be obvious. What can I try next?

String is indexed by String.Index, not Int – see for example stackoverflow.com/q/39676939/2976878 — Hamish
– Hamish, Commented Nov 14, 2017 at 23:37

Orion Edwards · Accepted Answer · 2017-11-28 06:30:35Z

10

Whoops. Seems I needed to just do this:

let idx = response.index(response.startIndex, offsetBy: 11)
let substr = response[idx...]

answered Nov 14, 2017 at 23:38

Orion Edwards

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1 Comment

You could also say let subsets = response.dropFirst(11) :)