Why does Swift use String.Index instead of Int for substrings?

[danmihai (Dan)]

Why is it that in Swift one has to work with String.Index, instead of Int?Like:

let myStr = "This is some string"

myStr[5...] // "is some string"

[xwu (Xiaodi Wu)]

Why are String offsets so complicated?

This comes up about once every 6 months. Here are some previous discussions: