Swift文字列数字インデックス文字
1693 ワード
文字列索引
s.substring(0,11) R13:String?=“helloswift”s[0] R14: Character? = “h”
extension String{
subscript(index:Int)->Character?{
return self[self.characters.startIndex.advancedBy(index)]
}
}
extension String{
subscript(index:Int)->String?{
get{
if index<0 || index>=self.characters.count{
return nil
}
return String(self[self.characters.startIndex.advancedBy(index)])
}
set(newValue){
self.replaceRange(self.characters.startIndex.advancedBy(index)...characters.startIndex.advancedBy(index+1),with:newValue!)
}
}
}
s.substring(0,11) R13:String?=“helloswift”s[0] R14: Character? = “h”