ArraysArraysVB .NET 2010

Declaring ArraysDeclaring ArraysDim Salary(15) As Integer ‘ 16 Elements

Salary(15) = 10000

for each s as Integer in SalaryConsole.WriteLine( s.toString( “Rs #.00”) )

next

Dim Names( ) As String = {“Joe”, “Peter “}

SORTING ARRAYSSORTING ARRAYS

System.array.Sort( arrayName )

System.array.Sort( arrayName,

startIndex, endIndex )

System.array.Sort( array1, array2

)

SEARCHING ARRAYSSEARCHING ARRAYS i = System.array.IndexOf( arrayName, Object )

i = System.array.IndexOf( arrayName, Object ,

startIndex)

i = System.array.IndexOf( arrayName, Object ,

startIndex, endIndex )

i = System.array.BinarySearch( arrayName, Object )

i = System.array.BinarySearch( arrayName,

startIndex, searchLength, Object )

-i – 1 ‘ one’s complement

ARRAYS . . .ARRAYS . . .

newArraay = System.array.Reverse( array1)

System.array.copy( array1, array2, count )

System.array.copyto(destinationArray,

sourceStart)

◦Both Copy and Copyto are one dimensional only

System.array.copy( sourceArray,

sourceStart, destinationArray,

destinationStart, count )

StructuresStructures

Structure Employee

Dim Name As String

Dim Salary As Decimal

Dim DOB as Date

End Structure

Dim E1 as New EmployeeE1.DOB = #01/31/2000#

Multidimensional Multidimensional ArraysArrays

Temperatures(2, 0) ‘ is the third city’s nameTemperatures(2, 1) ‘ is the third city’s temperature

Multidimensional Multidimensional Arrays . . .Arrays . . .Dim a(,) As Integer = {{10, 20, 30},

{11, 21, 31}, {12, 22, 32}}

Console.WriteLine(a(0, 1)) ’ will print 20

Console.WriteLine(a(2, 2)) ’ will print 32

To find out the number of dimensions :a.Rank ’ will print 2

Multidimensional Multidimensional Arrays . . .Arrays . . .

Console.WriteLine(a.GetLength(1)) ’ # of elements in second dimension = 3

Console.WriteLine(a.Length) ’ total elements = 9

Console.WriteLine(a.GetUpperBound(0))’ last index in the first dimension = 2

Console.WriteLine(a.GetLowerBound(1))’ first index in the second dimension = 3

LISTLIST

Dim names As New List(Of String)

Dim colors As New List(Of Color)

names.Add(“Richard”)

names.Add(“Nancy”)

colors.Add(Color.Red)

colors.Add(TextBox1.BackColor)

If names.Contains(name) Then

MsgBox("Duplicate ")

Iterating Through a ListIterating Through a ListFor i = 0 To Lst.Count - 1

{ process item Lst(i)}Next

For Each itm As String In Lst’ process item lst

Next

Dim itm As ObjectFor Each itm In aLst

{ process item itm }Next

DictionaryDictionary

Dim BDays As New Dictionary(Of String,

Date)

BDays.Add(“Manfred”, #3/24/1972#) ‘

Key & Value

BDays.Add(“Alfred”, #11/24/1959#)

To retrieve the birth date of Manfred,

use the following statement:

BDays(“Manfred”)

Dictionary . . Dictionary . .

Dictionary.ContainsKey(object)

Dictionary.ContainsValue(object)

Dim itm As Object

For Each itm In Dict.Values

Debug.WriteLine(itm)

Next

HashTableHashTable

Dim tmps As New Hashtable

tmps("Houston") = 81.3

tmps("Los Angeles") = 78.5

ArrayListArrayList

Dim aList As New ArrayList

‘ Don’t need to define the type as in

LIST

aList.capacity = 100

aList.Insert(index, object)

Lst.AddRange(colors)

Lst.InsertRange(index, objects)

Lst.SetRange(5, words) ‘overwrite

ArrayList . . .ArrayList . . .

aList.Remove(object)

Lst.RemoveRange(startIndex, count)

newLst = Lst.GetRange(index, count)

newList = ArrayList.Repeat(item,

count)

newList = aList.Repeat(item, count)

newList =

System.arrayList.Repeat(item, count)

ArrayList . . .ArrayList . . .

newList = aList.Revese()

newList = aList.Revese(startIndex

, endIndex)

Sorting and Searching are same

as in Arrays

Collection InitializersCollection InitializersDim letters As New ArrayList ( {"quick", "dog",

"fox", "lazy", "brown"})

Dim words = New List(Of String) ( {"the", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog“ } )

Dim numbers() As Decimal = {2.0, 12.99, 0.001, 1000.0, 10.01}

Dim P = New With {.First = "Evangelos", .Last = "Petroutsos"} ‘P is of an anonymous type

Sorting ListsSorting Lists

aLst.Sort()

aLst.Sort(comparer)

aLst.Sort(startIndex, endIndex,

comparer)

SortedListSortedListDim sList As New SortedListDim sList As New SortedList(New

comparer)sList.Add(key, item)

Searching ListsSearching ListsLst.IndexOf(object)

Lst.IndexOf(object, startIndex)

Lst.IndexOf(object, startIndex, length)

Dim index As Integer = Lst.BinarySearch(object)

Dim index As Integer = Lst.BinarySearch(object,

comparer)

Dim index As Integer = Lst.BinarySearch (startIndex,

length, object, comparer)

Implementing the IComparer Implementing the IComparer InterfaceInterface

Class customComparer : Implements IComparer

Public Function Compare(

ByVal o1 As Object, ByVal o2 As Object)

As Integer Implements IComparer.Compare

{ function’s code

Return -1, 0 and 1

}

End Function

End Class

Implementing the IComparer Implementing the IComparer Interface . . .Interface . . .

Dim CompareThem As New customComparer

aList.Sort(CompareThem)

aList.Sort(New customComparer)

aList.BinarySearch(object, New

customComparer)

File HandlingFile HandlingDim str As StreamReader = File.OpenText(path)

Dim txtLine As String

Dim words() As String

Dim Delimiters() As Char = { CType(" ", Char),

CType(".", Char), CType(",", Char), CType("?",

Char), CType("!", Char), CType(";", Char),

CType(":", Char), Chr(10), Chr(13), vbTab }

txtLine = str.ReadToEnd

words = txtLine.Split(Delimiters)