↑の Data の件、 Array と挙動が違って混乱を招くかも？

Welcome to Apple Swift version 4.0 (swiftlang-900.0.59 clang-900.0.34.2). Type :help for assistance. 1> var array = [2, 3, 5] array: [Int] = 3 values { [0] = 2 [1] = 3 [2] = 5 } 2> print(array.startIndex) 0 3> array.removeFirst() $R0: Int = 2 4> print(array.startIndex) 0