ITEC81: VB.NET Arrays (2) Lecture Notes PDF

# ITEC81: VB.NET Arrays (2) ## Rumer M. Bayot, Instructor ## Presentation Outline 1. VB.NET Arrays Properties and Methods 2. Array Properties 3. Array Methods ## VB.NET Arrays Properties and Methods - In VB.NET, arrays are used to store multiple values in a single variable. - Arrays in VB.NET...

# ITEC81: VB.NET Arrays (2) ## Rumer M. Bayot, Instructor ## Presentation Outline 1. VB.NET Arrays Properties and Methods 2. Array Properties 3. Array Methods ## VB.NET Arrays Properties and Methods - In VB.NET, arrays are used to store multiple values in a single variable. - Arrays in VB.NET are objects, and they come with several properties and methods that allow you to manipulate and interact with the data they contain. - **Properties** are characteristics of the array. - **Methods** are functions that perform operations on the array. ## Array Properties ### Length - Retrieves the total number of elements in the array (all dimensions). - The Length property works for single-dimensional and multi-dimensional arrays. ```vb.net Dim numbers() As Integer = {10, 20, 30, 40, 50} Console.WriteLine("Total Elements: " & numbers.Length) Dim matrix(2, 3) As Integer ' A 3x4 matrix Console.WriteLine("Total Elements: " & matrix.Length) ``` ### Rank - Returns the number of dimensions (or "rank") of the array. ```vb.net Dim oneDim() As Integer = {10, 20, 30} Dim twoDim(2, 3) As Integer ' 2D array Dim threeDim(2, 2, 2) As Integer ' 3D array Console.WriteLine("Rank of oneDim: " & oneDim.Rank) Console.WriteLine("Rank of twoDim: " & twoDim.Rank) Console.WriteLine("Rank of threeDim: " & threeDim.Rank) ``` ### GetLength(dimensionIndex) - Returns the size of the specified dimension of a multi-dimensional array. - Use GetLength(0) for rows, GetLength(1) for columns, etc. ```vb.net Dim matrix(2, 3) As Integer ' 3 rows, 4 columns Console.WriteLine("Number of Rows: " & matrix.GetLength(0)) Console.WriteLine("Number of Columns: " & matrix.GetLength(1)) ``` ### IsFixedSize - Returns True if the array size is fixed (always True for VB.NET arrays). ```vb.net Dim numbers() As Integer = {10, 20, 30} Console.WriteLine("Is Fixed Size: " & numbers.IsFixedSize) ``` ### IsReadOnly - Returns True if the array is read-only (always False for VB.NET arrays). ```vb.net Dim numbers() As Integer = {10, 20, 30} Console.WriteLine("Is Read-Only: " & numbers.IsReadOnly) ``` ### SyncRoot and IsSynchronized - Used for thread synchronization. Not typically used in single-threaded applications. ```vb.net Dim numbers() As Integer = {10, 20, 30} Console.WriteLine("Is Synchronized: " & numbers.IsSynchronized) ``` ## Array Methods ### GetValue(index) - Retrieves the value stored at a specified index in the array. - Works for both single and multi-dimensional arrays. ```vb.net Dim numbers() As Integer = {10, 20, 30} Console.WriteLine("Value at Index 1: " & numbers.GetValue(1)) Dim matrix(1, 1) As Integer matrix(0, 0) = 10 Console.WriteLine("Value at (0,0): " & matrix.GetValue(0, 0)) ``` ### SetValue(value, index) - Sets a value at the specified index in the array. - Works for single and multi-dimensional arrays. ```vb.net Dim numbers() As Integer = {10, 20, 30} numbers.SetValue(50, 1) Console.WriteLine("Value at Index 1: " & numbers(1)) Dim matrix(1, 1) As Integer matrix.SetValue(100, 0, 1) Console.WriteLine("Value at (0,1): " & matrix(0, 1)) ``` ### IndexOf - Finds the first occurrence of a specified value and returns its index. - Returns -1 if the value is not found. ```vb.net Dim numbers() As Integer = {10, 20, 30, 20} Dim index As Integer = Array.IndexOf(numbers, 20) Console.WriteLine("Index of 20: " & index) ``` ### LastIndexOf - Finds the last occurrence of a specified value and returns its index. ```vb.net Dim numbers() As Integer = {10, 20, 30, 20} Dim index As Integer = Array.LastIndexOf(numbers, 20) Console.WriteLine("Last Index of 20: " & index) ``` ### Sort - Sorts the array in ascending order. - Can sort arrays of numbers, strings, or objects (requires a comparer for objects). ```vb.net Dim numbers() As Integer = {30, 10, 20} Array.Sort(numbers) Console.WriteLine("Sorted Array: " & String.Join(", ", numbers)) ``` ### Reverse - Reverses the order of elements in the array. ```vb.net Dim numbers() As Integer = {10, 20, 30} Array.Reverse(numbers) Console.WriteLine("Reversed Array: " & String.Join(", ", numbers)) ``` ### Clear - Sets all elements in the array to their default values (e.g., 0 for integers, Nothing for objects). ```vb.net Dim numbers() As Integer = {10, 20, 30} Array.Clear(numbers, 0, numbers.Length) Console.WriteLine("Cleared Array: " & String.Join(", ", numbers)) ``` ### Copy - Copies elements from one array to another. ```vb.net Dim source() As Integer = {10, 20, 30} Dim destination(2) As Integer Array.Copy(source, destination, 3) Console.WriteLine("Copied Array: " & String.Join(", ", destination)) ``` ### Resize - Resizes the array to the specified size. If the new size is larger, new elements are initialized to their default values. ```vb.net Dim numbers() As Integer = {10, 20, 30} Array.Resize(numbers, 5) numbers(3) = 40 numbers(4) = 50 Console.WriteLine("Resized Array: " & String.Join(", ", numbers)) ``` ### BinarySearch - Searches for a value in a sorted array using the binary search algorithm. ```vb.net Dim numbers() As Integer = {10, 20, 30, 40, 50} Console.WriteLine("Index of 30: " & Array.BinarySearch(numbers, 30)) ``` ### Find - Finds the first element that matches a specified condition. ```vb.net Dim numbers() As Integer = {10, 20, 30} Dim result As Integer = Array.Find(numbers, Function(x) x > 15) Console.WriteLine("First Element > 15: " & result) ``` ### FindAll - Finds all elements that match a specified condition. ```vb.net Dim numbers() As Integer = {10, 20, 30, 40} Dim results() As Integer = Array.FindAll(numbers, Function(x) x > 20) Console.WriteLine("Elements > 20: " & String.Join(", ", results)) ``` ## Questions? 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