如何获取字符串的第n个字符？我试过括号([])存取器没有运气。
var string = "Hello,world!" var firstChar = string[0] // Throws error
extension String {
subscript (i: Int) -> Character {
return self[self.startIndex.advancedBy(i)]
}
subscript (i: Int) -> String {
return String(self[i] as Character)
}
subscript (r: Range<Int>) -> String {
let start = startIndex.advancedBy(r.startIndex)
let end = start.advancedBy(r.endIndex - r.startIndex)
return self[Range(start ..< end)]
}
}
现在，这些都等于true。
"abcde"[0] == "a" "abcde"[0...2] == "abc" "abcde"[2..<4] == "cd"
