.net 基礎知識大雜燴(4) ——數組

數組

任務	C#	VB
建立一個長度為5的一維數組，使用預設值作為初值	int[] ages = new int[5]; Console.WriteLine(ages.Length); //=> 5 Console.WriteLine(ages.Rank);   //=> 1 Console.WriteLine(ages.GetLowerBound(0)); // => 0 Console.WriteLine(ages.GetUpperBound(0)); // => 4	Dim ages(4) As Integer Console.WriteLine(ages.Length)  '=> 5 Console.WriteLine(ages.Rank)  '=> 1 Console.WriteLine(ages.GetLowerBound(0))  ' => 0 Console.WriteLine(ages.GetUpperBound(0))  '=> 4
建立一個長度為5的一維數組，指定初始值	int[] ages = new int[5] { 1, 3, 5, 7, 9 }; // OK int[] ages1 = new int[] { 1, 3, 5, 7, 9 }; // OK int[] ages2 = new int[6] { 1, 3, 5, 7, 9 }; // 編譯錯誤 Console.WriteLine(ages.Length); //=> 5 Console.WriteLine(ages.Rank);   //=> 1 Console.WriteLine(ages.GetLowerBound(0)); // => 0 Console.WriteLine(ages.GetUpperBound(0)); // => 4	Dim ages() As Integer = New Integer(4) {1, 3, 5, 7, 9} ' OK Dim ages1() As Integer = New Integer() {1, 3, 5, 7, 9} ' OK Dim ages2() As Integer = New Integer(5) {1, 3, 5, 7, 9} ' 編譯錯誤 Console.WriteLine(ages.Length)  '=> 5 Console.WriteLine(ages.Rank)  '=> 1 Console.WriteLine(ages.GetLowerBound(0))  ' => 0 Console.WriteLine(ages.GetUpperBound(0))  '=> 4
建立一個2行3列二維數組，使用預設值作為初值	int[,] t = new int[2, 3]; Console.WriteLine(t.Length); //=> 6 Console.WriteLine(t.Rank);   //=> 2 Console.WriteLine(t.GetLength(0)); // => 2 Console.WriteLine(t.GetLowerBound(0)); // => 0 Console.WriteLine(t.GetUpperBound(0)); // => 1 Console.WriteLine(t.GetLowerBound(1)); // => 0 Console.WriteLine(t.GetUpperBound(1)); // => 2 Console.WriteLine(t.GetLength(1)); // => 3	Dim t(1, 2) As Integer Console.WriteLine(t.Length)  '=> 6 Console.WriteLine(t.Rank)  '=> 2 Console.WriteLine(t.GetLength(0))  '=> 2 Console.WriteLine(t.GetLowerBound(0))  '=> 0 Console.WriteLine(t.GetUpperBound(0))  '=> 1 Console.WriteLine(t.GetLowerBound(1))  '=> 0 Console.WriteLine(t.GetUpperBound(1))  '=> 2 Console.WriteLine(t.GetLength(1))  '=> 3
建立一個2行3列二維數組，指定初始值	int[,] t = new int[2,3] { { 1, 2, 3 },                           { 4, 5, 6 } }; int[,] t1 = new int[,] { { 1, 2, 3 },                          { 4, 5, 6 } }; Console.WriteLine(t.Length); //=> 6 Console.WriteLine(t.Rank);   //=> 2 Console.WriteLine(t.GetLength(0)); // => 2 Console.WriteLine(t.GetLowerBound(0)); // => 0 Console.WriteLine(t.GetUpperBound(0)); // => 1 Console.WriteLine(t.GetLowerBound(1)); // => 0 Console.WriteLine(t.GetUpperBound(1)); // => 2 Console.WriteLine(t.GetLength(1)); // => 3	Dim t(,) As Integer = New Integer(1, 2) {{1, 2, 3}, _                                          {4, 5, 6}} Dim t1(,) As Integer = New Integer(,) {{1, 2, 3}, _                                        {4, 5, 6}} Console.WriteLine(t.Length)  '=> 6 Console.WriteLine(t.Rank)  '=> 2 Console.WriteLine(t.GetLength(0))  '=> 2 Console.WriteLine(t.GetLowerBound(0))  '=> 0 Console.WriteLine(t.GetUpperBound(0))  '=> 1 Console.WriteLine(t.GetLowerBound(1))  '=> 0 Console.WriteLine(t.GetUpperBound(1))  '=> 2 Console.WriteLine(t.GetLength(1))  '=> 3
建立一個長度為5下標為1的一維數組，使用預設值作為初值	Array t = Array.CreateInstance(typeof(string), new int[] { 5 }, new int[] { 1 }); Console.WriteLine(t.Length); //=> 5 Console.WriteLine(t.Rank);   //=> 1 Console.WriteLine(t.GetLength(0)); // => 5 Console.WriteLine(t.GetLowerBound(0)); // => 1 Console.WriteLine(t.GetUpperBound(0)); // => 5	Dim t As Array = Array.CreateInstance(GetType(Integer), New Integer() {5}, New Integer() {1}) Console.WriteLine(t.Length)  '=> 5 Console.WriteLine(t.Rank)  '=> 1 Console.WriteLine(t.GetLength(0))  '=> 5 Console.WriteLine(t.GetLowerBound(0))  '=> 1 Console.WriteLine(t.GetUpperBound(0))  '=> 5
建立一個2行3列下標為1的二維數組，使用預設值作為初值	int[,] t = (int[,])Array.CreateInstance(typeof(int), new int[] {2,3}, new int[] {1,1}); Console.WriteLine(t.Length); //=> 6 Console.WriteLine(t.Rank);   //=> 2 Console.WriteLine(t.GetLength(0)); // => 2 Console.WriteLine(t.GetLowerBound(0)); // => 1 Console.WriteLine(t.GetUpperBound(0)); // => 2 Console.WriteLine(t.GetLowerBound(1)); // => 1 Console.WriteLine(t.GetUpperBound(1)); // => 3 Console.WriteLine(t.GetLength(1)); // => 3	Dim t(,) As Integer = Array.CreateInstance(GetType(Integer), New Integer() {2, 3}, New Integer() {1, 1}) Console.WriteLine(t.Length)  '=> 6 Console.WriteLine(t.Rank)  '=> 2 Console.WriteLine(t.GetLength(0))  '=> 2 Console.WriteLine(t.GetLowerBound(0))  '=> 1 Console.WriteLine(t.GetUpperBound(0))  '=> 2 Console.WriteLine(t.GetLowerBound(1))  '=> 1 Console.WriteLine(t.GetUpperBound(1))  '=> 3 Console.WriteLine(t.GetLength(1))  '=> 3
改變數組長度	int[] t = new int[2]; Array.Resize(ref t, 3); Console.WriteLine(t.Length); //=> 3 Console.WriteLine(t.Rank);   //=> 1 Console.WriteLine(t.GetLength(0)); // => 3 Console.WriteLine(t.GetLowerBound(0)); // => 0 Console.WriteLine(t.GetUpperBound(0)); // => 2	Dim t(2) As Integer Array.Resize(t, 3) Console.WriteLine(t.Length)  '=> 3 Console.WriteLine(t.Rank)  '=> 1 Console.WriteLine(t.GetLength(0))  '=> 3 Console.WriteLine(t.GetLowerBound(0))  '=> 0 Console.WriteLine(t.GetUpperBound(0))  '=> 2
參考型別數組的強制類型轉換	string[] s = new string[3]; object[] os = s; s = (string[])os;	Dim s(2) As String Dim os() As Object = s s = os
實值型別數組的強制類型轉換(VS2005)	int[] a = new int[2]; decimal[] da1 = a; // 編譯錯誤 decimal[] da2 = (int[])a; // 編譯錯誤 decimal[] da = Array.ConvertAll(a,     new Converter(         delegate(int old)         {             return old;         })); // OK	Dim a(2) As Integer Dim da() As Decimal = Array.ConvertAll(a, _     New Converter(Of Integer, Decimal)(AddressOf ConvertInt)) … Function ConvertInt(ByVal old As Integer) As Decimal     Return old End Function
實值型別數組的強制類型轉換(VS2008)	int[] a = new int[2]; decimal[] da = Array.ConvertAll(a,     new Converter(old => old));	Dim a(2) As Integer Dim da() As Decimal = Array.ConvertAll(Of Integer, Decimal)(a, _     New Converter(Of Integer, Decimal)(Function(old) old))
建立一個交錯數組（即數組的數組）	int[][] a = new int[2][]; Console.WriteLine(a[0] == null); //=> True	Dim a(2)() As Integer Console.WriteLine(a(0) Is Nothing) '=> True
建立一個交錯數組，並初始化（例1）	int[][] a = new int[2][] { new int[2], new int[3] }; Console.WriteLine(a[0].Length); //=> 2 Console.WriteLine(a[1].Length); //=> 3	Dim m(1) As Integer Dim n(2) As Integer Dim a()() As Integer = New Integer(1)() {m, n} Console.WriteLine(a(0).Length) '=> 2 Console.WriteLine(a(1).Length) '=> 3
建立一個交錯數組，並初始化（例2）	int[][] a = new int[2][] { new int[2] { 1, 2 },                            new int[3] { 11, 22, 33 } }; Console.WriteLine(a[0][0]); //=> 1 Console.WriteLine(a[1][2]); //=> 33	Dim m() As Integer = New Integer(1) {1, 2} Dim n() As Integer = New Integer(2) {11, 22, 33} Dim a()() As Integer = New Integer(1)() {m, n} Console.WriteLine(a(0)(0)) '=> 1 Console.WriteLine(a(1)(2)) '=> 33