【SwiftUI】文字列Stringの任意の場所を抽出する - Qiita

extension String { func pickupString(sNum:Int,eNum:Int) -> String{ let startIndex = self.index(self.startIndex, offsetBy: sNum) let endIndex = self.index(self.endIndex, offsetBy: -(self.count - eNum + 1)) return String(self[startIndex...endIndex]) } }