Catch Exception for String.Substring
public class Test
public Shared Sub Main
Dim strCaption As String
strCaption = "Answer"
Try
Console.WriteLine(strCaption.Substring(10, 1))
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
End Sub
End classstartIndex cannot be larger than length of string.
Parameter name: startIndex
Change tab to space
Public Class Tester
Public Shared Sub Main
Dim tabs As String = "This~is~~a~tabbed~~~string".Replace("~"c, vbTab)
Dim spaces As String = TabsToSpaces(tabs, 8)
Dim periods As String = spaces.Replace(" "c, "."c)
Console.WriteLine(tabs)
Console.WriteLine(spaces)
Console.WriteLine(periods)
End Sub
Public Shared Function TabsToSpaces(ByVal source As String, ByVal tabSize As Integer) As String
Dim result As New System.Text.StringBuilder
Dim counter As Integer
For counter = 0 To source.Length - 1
If (source.Chars(counter) = vbTab) Then
Do
result.Append(Space(1))
Loop Until ((result.Length Mod tabSize) = 0)
Else
result.Append(source.Chars(counter))
End If
Next counter
Return result.ToString()
End Function
End ClassThis is a tabbed string
This is a tabbed string
This....is..............a.......tabbed..................string
Check a Credit card number
" Quote from
"Visual Basic 2005 Cookbook Solutions for VB 2005 Programmers
"by Tim Patrick (Author), John Craig (Author)
"# Publisher: O"Reilly Media, Inc. (September 21, 2006)
"# Language: English
"# ISBN-10: 0596101775
"# ISBN-13: 978-0596101770
Public Class Tester
Public Shared Sub Main
Console.WriteLine(VerifyCreditCard("123123123123123123"))
End Sub
Private Shared Function VerifyCreditCard(ByVal cardNumber As String) As Boolean
" ----- Given a card number, make sure it is valid. This method
" uses the Luhn algorithm to verify the number. This routine
" assumes that cardNumber contains only digits.
Dim counter As Integer
Dim digitTotal As Integer
Dim holdValue As Integer
Dim checkDigit As Integer
Dim calcDigit As Integer
Dim useCard As String
" ----- Perform some initial checks.
useCard = Trim(cardNumber)
If (IsNumeric(useCard) = False) Then Return False
" ----- Separate out the last digit, the check digit. For cards with
" an odd number of digits, prepend with a zero.
If ((Len(useCard) Mod 2) <> 0) Then useCard = "0" & useCard
checkDigit = useCard.Substring(Len(useCard) - 1, 1)
useCard = useCard.Substring(0, Len(useCard) - 1)
" ----- Process each digit.
digitTotal = 0
For counter = 1 To Len(useCard)
If ((counter Mod 2) = 1) Then
" ----- This is an odd digit position. Double the number.
holdValue = CInt(Mid(useCard, counter, 1)) * 2
If (holdValue > 9) Then
" ----- Break the digits (e.g., 19 becomes 1+9).
digitTotal += (holdValue \ 10) + (holdValue - 10)
Else
digitTotal += holdValue
End If
Else
" ----- This is an even digit position. Simply add it.
digitTotal += CInt(Mid(useCard, counter, 1))
End If
Next counter
" ----- Calculate the 10"s complement of both values.
calcDigit = 10 - (digitTotal Mod 10)
If (calcDigit = 10) Then calcDigit = 0
If (checkDigit = calcDigit) Then Return True Else Return False
End Function
End ClassFalse
Copy characters from string1 into character Array
Module Tester
Sub Main()
Dim string1 As String
Dim characterArray As Char()
Dim i As Integer
Dim quotes As Char = ChrW(34)
string1 = "hello there"
characterArray = New Char(5) {}
string1.CopyTo(0, characterArray, 0, 5)
For i = 0 To characterArray.GetUpperBound(0)
Console.WriteLine(characterArray(i))
Next
End Sub " Main
End Moduleh
e
l
l
o
Count Vowels
Imports System.IO
public class Test
public Shared Sub Main
Console.WriteLine("VOWELS COUNTED: " & CountTheVowels("asdffdsaasdf"))
End Sub
Private Shared Function CountTheVowels(ByVal strSomeString As String) As Integer
Dim intCount As Integer = 1
Dim intTotal As Integer = 0
Dim intPosition As Integer
"Loop through the string and count the vowels.
Do While intCount <= strSomeString.Length
intPosition = InStr("aeio", strSomeString.Substring(intCount, 1).ToLower)
If intPosition > 0 Then
intTotal += 1
End If
Loop
Return intTotal
End Function
End classDeclare String Variable and assign value
Module Module1
Sub Main()
Dim EmployeeName As String
Dim EmployeePhoneNumber As String
Dim EmployeeSalary As Double
Dim NumberOfEmployees As Integer
EmployeeName = "James Bond"
EmployeePhoneNumber = "555-1212"
EmployeeSalary = 45.0
NumberOfEmployees = 1
Console.WriteLine("Number of employees: " & NumberOfEmployees)
Console.WriteLine("Employee name: " & EmployeeName)
Console.WriteLine("Employee phone number: " & EmployeePhoneNumber)
Console.WriteLine("Employee salary: " & EmployeeSalary)
End Sub
End ModuleNumber of employees: 1
Employee name: James Bond
Employee phone number: 555-1212
Employee salary: 45
Demonstrating method GetHashCode of class String
Module Tester
Sub Main()
Dim string1 As String = "hello"
Dim string2 As String = "Hello"
Console.WriteLine(string1.GetHashCode() )
Console.WriteLine(string2.GetHashCode())
End Sub " Main
End Module-695839
-694847
Demonstrating String class constructors
Module Tester
Sub Main()
Dim characterArray As Char()
Dim quotes As Char = ChrW(34)
Dim originalString, string1, string2, string3, string4 As String
characterArray = New Char() {"A"c, "B"c, "C"c, "D"c, "E"c, "F"c, " "c, "G"c, "H"c}
originalString = "test"
string1 = originalString
string2 = New String(characterArray)
string3 = New String(characterArray, 6, 3)
string4 = New String("C"c, 5)
Console.WriteLine(string1)
Console.WriteLine("string2 = " & string2 )
Console.WriteLine("string3 = " & string3 )
Console.WriteLine("string4 = " & string4 )
End Sub " Main
End Moduletest
string2 = ABCDEF GH
string3 = GH
string4 = CCCCC
Get string morse code
Public Class Tester
Public Shared Sub Main
Dim source As String = "Hello world!"
Dim characters As String = _
"~ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.,:?"-/"""
Dim morse() As String = { _
"?", ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", _
"..", ".---", "-.-", ".-..", "--", "-.", "---", ".--.", _
"--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", _
"-.--", "--..", "-----", ".----", "..---", "...--", _
"....-", ".....", "-....", "--...", "---..", "----.", _
".-.-.-", "--..--", "---...", "..--..", ".----.", _
"-....-", "-..-.", ".-..-."}
Dim counter As Integer
Dim position As Integer
For counter = 0 To source.Length - 1
position = characters.IndexOf(Char.ToUpper( _
source.Chars(counter)))
If (position < 0) Then position = 0
Console.Write (source.Substring(counter, 1) & " ")
Console.WriteLine(morse(position))
Next counter
End Sub
End ClassH ....
e .
l .-..
l .-..
o ---
?
w .--
o ---
r .-.
l .-..
d -..
! ?
Insert method returns the resulting string
public class Test
public Shared Sub Main
Dim s1 As New String("Greeting")
s1.Insert(4, "sdss") "DOES NOT CHANGE S1!!!!
s1 = s1.Insert(8, "s") "changes Greeting to Greetings
Console.WriteLine(s1.Length)
Console.WriteLine(s1)
End Sub
End class9
Greetings
Insert sub string by index
Option Strict On
Imports System
Class Tester
Public Shared Sub Main( )
Dim s1 As String = "abcd"
Dim s2 As String = "ABCD"
Dim s3 As String = "AAAAs "
s3 = s3 & "development"
Dim s5 As String = String.Copy(s2) "
Console.WriteLine("s5 copied from s2: {0}", s5)
Console.WriteLine("String s3 is {0} characters long. ",s5.Length)
Console.WriteLine("s3: {0}", s3)
" hold the location of provides as an integer
Dim location As Integer = s3.IndexOf("a")
Dim s10 As String = s3.Insert(location, "u")
Console.WriteLine("s10: {0}", s10)
End Sub "Main
End Class "Testers5 copied from s2: ABCD
String s3 is 4 characters long.
s3: AAAAs development
Unhandled Exception: System.ArgumentOutOfRangeException: Index was out of range. Must be non-negativ
e and less than the size of the collection.
Parameter name: startIndex
at System.String.Insert(Int32 startIndex, String value)
at Tester.Main()
Join string
Imports System.Collections
public class Test
public Shared Sub Main
Dim s() As String = {"one", "two", "three"} "a string array
Dim s2 As String
s2 = s2.Join(", ", s)
Console.WriteLine(s2)
End Sub
End classone, two, three
Make a reference copy
Public Class Tester
Public Shared Sub Main
Dim arrayA() As String = {"One", "Two", "Three", "Four", "Five", "Six"}
Console.WriteLine(Join(arrayA, ","))
Dim arrayB() As String = {"A", "B", "C", "D", "E", "E", "F", "G", "H"}
Console.WriteLine(Join(arrayB, ","))
" ----- Make a reference copy.
Dim arrayC() As String = arrayA
Console.WriteLine(Join(arrayC, ","))
End Sub
End ClassOne,Two,Three,Four,Five,Six
A,B,C,D,E,E,F,G,H
One,Two,Three,Four,Five,Six
Read String value from Keyboard
Module Module1
Sub Main()
Dim FirstName As String
Console.Write("Name: ")
FirstName = Console.ReadLine()
Console.WriteLine(FirstName)
End Sub
End ModuleName: name
name
Reverse a string
public class Test
public Shared Sub Main
Dim objTS As TimeSpan
Dim dteStart As Date
Dim strText As String
Dim strChar As String
Dim intChar As Integer
dteStart = Now()
strText = "12345678"
Dim intLen As Integer = Len(strText)
For intChar = 1 To CInt(intLen / 2)
strChar = Mid(strText, intChar, 1)
Mid(strText, intChar, 1) = Mid(strText, intLen - intChar - 1, 1)
Mid(strText, intLen - intChar - 1) = strChar
Next
objTS = Now().Subtract(dteStart)
Console.WriteLine(objTS.ToString)
Console.WriteLine(strText)
End Sub
End class00:00:00
65342178
String.Empty
Option Strict On
Public Module modMain
Public Sub Main()
Console.WriteLine(String.Empty)
End Sub
End ModuleString Length property
Module Tester
Sub Main()
Dim string1 As String
Dim characterArray As Char()
Dim i As Integer
Dim quotes As Char = ChrW(34)
string1 = "hello there"
characterArray = New Char(5) {}
Console.WriteLine("Length of string1: " & string1.Length)
End Sub " Main
End ModuleLength of string1: 11
String operation timing
Public Class Tester
Public Shared Sub Main
Dim content As String = ""
Dim result As New System.Text.StringBuilder
Dim counter As Integer
Dim dateTime1 As Date
Dim dateTime2 As Date
Dim dateTime3 As Date
Dim loopCount As Integer = 15000
dateTime1 = Now
For counter = 1 To loopCount
content &= counter.ToString()
Next counter
dateTime2 = Now
For counter = 1 To loopCount
result.Append(counter.ToString())
Next counter
dateTime3 = Now
content = String.Format( _
"First loop took {0:G4} ms, the second took {1:G4} ms.", _
dateTime2.Subtract(dateTime1).TotalMilliseconds, _
dateTime3.Subtract(dateTime2).TotalMilliseconds)
Console.WriteLine(content)
End Sub
End ClassFirst loop took 1734 ms, the second took 0 ms.
SubString
Option Strict On
Imports System
Class Tester
Public Shared Sub Main( )
Dim s1 As String = "One Two Three Four"
Dim index As Integer
index = s1.LastIndexOf(" ")
Dim s2 As String = s1.Substring((index + 1))
s1 = s1.Substring(0, index)
index = s1.LastIndexOf(" ")
Dim s3 As String = s1.Substring((index + 1))
s1 = s1.Substring(0, index)
index = s1.LastIndexOf(" ")
Dim s4 As String = s1.Substring((index + 1))
s1 = s1.Substring(0, index)
index = s1.LastIndexOf(" ")
Dim s5 As String = s1.Substring((index + 1))
Console.WriteLine("s1: {0}", s1)
Console.WriteLine("s2: {0}", s2)
Console.WriteLine("s3: {0}", s3)
Console.WriteLine("s4: {0}", s4)
Console.WriteLine("s5: {0}", s5)
End Sub "Main
End Class "Testers1: One
s2: Four
s3: Three
s4: Two
s5: One
ToString
Public Class Tester
Public Shared Sub Main
Dim someInt As Integer = 123
Dim someDouble As Double = Math.PI
Dim someString As String = "Testing"
Dim someDate As Date = #7/4/1776 9:10:11 AM#
Dim someDecimal As Decimal = 1D / 3D
Dim result As New System.Text.StringBuilder
result.Append("someInt.ToString ")
result.AppendLine(someInt.ToString())
result.Append("someDouble.ToString ")
result.AppendLine(someDouble.ToString())
result.Append("someString.ToString ")
result.AppendLine(someString.ToString())
result.Append("someDate.ToString ")
result.AppendLine(someDate.ToString())
result.Append("someDecimal.ToString ")
result.Append(someDecimal.ToString())
Console.WriteLine(result.ToString())
End Sub
End ClasssomeInt.ToString 123
someDouble.ToString 3.14159265358979
someString.ToString Testing
someDate.ToString 04/07/1776 9:10:11 AM
someDecimal.ToString 0.3333333333333333333333333333
