Tutorial [Beginner-Friendly] [VB.NET] String Manipulation Snippets Vault [30 Operations]

Scythe · 04-14-2014, 03:57 PM

So, let's start with a short introduction to what a string is.

In programming, a string is defined as data type that can represent a text, which is consisted from a collection of characters that contains spaces and numerical values as well. Unlike the "Integer" declaration, which can only contain a single numerical value.

Here are different methods of declaring a string:

Code:
'Declare without initializing. 
Dim MyString As String

'Initialize to null. 
Dim MyString As String = Nothing

'Declare with a regular string literal
Dim MyString As String = "Hello, world!"

NOTES:
- The separator after #25 means I'm advancing into the details.
- Dear guests, benefit from the code. Don't ripoff.
- Last thread update: 15/4/2014

1. Replace Function - creates changes in the contents of the string

Code:
	Dim Original As String = "The world is awful"
	Dim Modified As String = Original.Replace("awful", "beautiful")
	MsgBox(Modified)

2. Calculate String Length - calculates how many characters are in the string

Code:
Dim Word As String = "Hello"
        Dim Wordlength As Integer = Word.Length

        MsgBox(Wordlength) 'Output should be 5

3. Reverse String - creates a mirrored text

Code:
Function ReverseString(ByVal value As String) As String

        Dim chr() As Char = value.ToCharArray()
        Array.Reverse(chr)
        Return New String(chr)

    End Function

'Usage:

        Dim MyString As String = "Hello, world"
        Dim ReversedString As String = ReverseString(MyString)
        MsgBox(ReversedString)

4. Construct a String - creates a string from a sequence of characters

Code:
Dim Letters As Char() = {"A"c, "B"c, "C"c, "D"c, "E"c, "F"c, "G"c}
        Dim Alphabet As New String(Letters)

        MsgBox(letters)

5. ToUpper - converts all lowercase characters to uppercase characters

Code:
Dim MyString As String = "hello, world"
        MyString = MyString.ToUpper()
        MsgBox(MyString)

6. ToLower - converts all uppercase characters to lowercase characters

Code:
Dim MyString As String = "HELLO, WORLD"
        MyString = MyString.ToLower()
        MsgBox(MyString)

7. ToSentence - capitalizes first character and every first character after ".", "?", "!"

Code:
Public Function SentenceCase(ByVal MyString() As Char) As String

        Dim sentenceStart As Boolean = True
        Dim I As Integer
        MyString = CStr(MyString).ToLower
        For I = 0 To Len(MyString) - 1
            If sentenceStart Then MyString(I) = CStr(MyString(I)).ToUpper
            If MyString(I) <> " " Then sentenceStart = InStr(".!?", MyString(I))
        Next
        Return MyString

 End Function

'Usage:

        Dim MyString As String = "hello! this is Toxin. how are you?"
        Dim ModifiedString As String = SentenceCase(MyString)
        MsgBox(ModifiedString)

8. ToInverted - creates a mixture of uppercase and lowercase characters

Code:
Private Function ToInverted(ByVal MyString As String) As String

        Dim sResult As String = ""
        Dim sChar As String = ""
        Dim i As Integer
        Dim capital As Boolean = True
        For i = 0 To MyString.Length - 1
            capital = Not capital
            sChar = MyString.Substring(i, 1)
            If capital Then
                sResult &= sChar.ToUpper
            Else
                sResult &= sChar.ToLower
            End If
        Next
        Return sResult

    End Function

'Usage:

        Dim MyString As String = "hello! this is Toxin. how are you?"
        Dim ModifiedString As String = ToInverted(MyString)
        MsgBox(ModifiedString)

9. Split Strings - creates a new line after each word

Code:
Dim MyString As String = "i use sinisterly"
        Dim SplittedString As String() = MyString.Split(New Char() {" "c})
        Dim word As String

        For Each word In SplittedString
            MsgBox(word)
        Next

10. Join Strings - joins splitted strings and creates a sentence

Code:
Dim StringArray(3) As String
        StringArray(0) = "sinisterly"
        StringArray(1) = "is"
        StringArray(2) = "really"
        StringArray(3) = "nice"

        Dim JoinedString As String = String.Join(" ", StringArray)
        MsgBox(JoinedString)

11. Join Strings Without Using String.Join - concatenate strings and creates a sentence

Code:
Dim MyString1 As String = "The forums of Sinisterly "
        Dim MyString2 As String = "are full of joy"
        Dim CompleteString As String

        CompleteString = MyString1 + MyString2
        MsgBox(CompleteString)

12. String.Contains - checks if string contains the specified word

Code:
Dim MyString As String = "hello everyone"
        If MyString.Contains("Hello") Then
            MsgBox("true")
        Else
            MsgBox("false")
        End If

13. String.StartsWith - checks if string starts with the specified word

Code:
Dim MyString As String = "Sinisterly is awesome"

        If MyString.StartsWith("Sinisterly", StringComparison.OrdinalIgnoreCase) Then
            MsgBox("true")
        Else
            MsgBox("false")
        End If

        'NOTE:
        ' "StringComparison.OrdinalIgnoreCase" ignores the character case wether it's upper or lower

14. String.EndsWith - checks if string ends with the specified word

Code:
Dim MyString As String = "Sinisterly is awesome"

        If MyString.EndsWith("awesome", StringComparison.OrdinalIgnoreCase) Then
            MsgBox("true")
        Else
            MsgBox("false")
        End If

        'NOTE:
        ' "StringComparison.OrdinalIgnoreCase" ignores the character case wether it's upper or lower

15. String.Trim - deletes leading and trailing instances of the specified character

Code:
Dim MyString As String = "%%No Percentage%%"
        Dim TrimmedString As String = MyString.Trim("%")

        MsgBox(TrimmedString)

16. String.LTrim - deletes empty spaces (nullspace) at the beginning of the string

Code:
Dim MyString As String = "       hello, world"
        Dim TrimmedString As String = LTrim(MyString)

        MsgBox(TrimmedString)

17. String.RTrim - deletes empty spaces (nullspace) at the end of the string

Code:
Dim MyString As String = "hello, world       "
        Dim TrimmedString As String = RTrim(MyString)

        MsgBox(TrimmedString)

18. Trim Punctuation - deletes punctuation characters, such as "!","?", "*", etc.

Code:
Function TrimPunctuation(ByVal value As String)
        
        '// This function is not written by me (Toxin)
        ' Count leading punctuation.
        Dim removeFromStart As Integer = 0
        For i As Integer = 0 To value.Length - 1 Step 1
            If Char.IsPunctuation(value(i)) Then
                removeFromStart += 1
            Else
                Exit For
            End If
        Next

        ' Count trailing punctuation.
        Dim removeFromEnd As Integer = 0
        For i As Integer = value.Length - 1 To 0 Step -1
            If Char.IsPunctuation(value(i)) Then
                removeFromEnd += 1
            Else
                Exit For
            End If
        Next

        ' Remove leading and trailing punctuation.
        Return value.Substring(removeFromStart,value.Length - removeFromEnd - removeFromStart)

    End Function

'Usage:

        Dim values() As String = {"One?", "--two--", "...three!","four", "five*"}

        For Each value As String In values
            MsgBox(TrimPunctuation(value))
        Next

19. Count Words in String with RegEx - counts how many words are in the string

Code:
Dim MyString As String = "These are four words"
        Dim CoutWords As System.Text.RegularExpressions.MatchCollection = System.Text.RegularExpressions.Regex.Matches(MyString, "[\S]+")

        MessageBox.Show(CoutWords.Count.ToString())

20. Count Chars in String with RegEx - counts how many characters are in the string

Code:
Dim MyString As String = "four"
        Dim CountChars As System.Text.RegularExpressions.MatchCollection = System.Text.RegularExpressions.Regex.Matches(MyString, ".")
        MessageBox.Show(CountChars.Count.ToString())

21. Delimited String - Adds a delimiter in the array of strings

Code:
Dim StringArray As String() = New String(2) {" 1 ", " 2 ", " 3 "}
        Dim ModifiedString As String = String.Join("|", StringArray)
        MsgBox(ModifiedString)

22. Space To Tab - converts spaces to tabs

Code:
Dim MyString As String = "Sinisterly is nice"
        Dim ModifiedString As String = MyString.Replace(" ", vbTab)

        MsgBox(ModifiedString)

23. Tab To Space- converts tabs to spaces

Code:
Dim MyString As String = "Sinisterly" & vbTab & "is" & vbTab & "nice"
        Dim ModifiedString As String = MyString.Replace(vbTab, " ")

        MsgBox(ModifiedString)

24. Space To NewLine - converts spaces to new lines

Code:
Dim MyString As String = "Sinisterly is nice"
        Dim ModifiedString As String = MyString.Replace(" ", ControlChars.Lf)

        MsgBox(ModifiedString)

25. EOL To Space - converts End of Line to sapce

Code:
Dim MyString As String = "Sinisterly" & vbLf & "is" & vbLf & "nice"
        Dim ModifiedString As String = MyString.Replace(ControlChars.Lf, " ")

        MsgBox(ModifiedString)

26. ASCII To HEX - converts normal text to Hex

Code:
Dim MyString As String = "Sinisterly is nice".ToCharArray
            Dim HexString As String
            Dim sHex As String = ""
            For Each ch As Char In MyString
                sHex += Convert.ToString(Convert.ToInt32(ch), 16) & " "
            Next
            HexString = sHex
            MsgBox(HexString)

27. HEX To ASCII - converts Hex to normal text

Code:
Dim MyHexString As String = "53 69 6e 69 73 74 65 72 6c 79 20 69 73 20 6e 69 63 65"
        Dim MyASCIIString As String
        Dim arrStrings As String() = MyHexString.Trim(" "c).Split(" "c)
        Dim sText As String = ""
        For Each st As String In arrStrings
            sText += Convert.ToChar(Convert.ToInt32(st, 16))
        Next
        MyASCIIString = sText
        MsgBox(MyASCIIString)

28. ASCII To Base64 - converts normal text to Base64

Code:
Dim MyString As String = "Sinisterly is nice"
        Dim Base64String As String
        Dim [Byte] As Byte() = System.Text.Encoding.UTF8.GetBytes(MyString)

        Base64String = Convert.ToBase64String([Byte])
        MsgBox(Base64String)

29. Base64 To ASCII - converts Base64 to normal text

Code:
Dim MyBase64String As String = "U2luaXN0ZXJseSBpcyBuaWNl"
        Dim MyASCIIString As String
        Dim [Byte] As Byte() = Convert.FromBase64String(MyBase64String)

        MyASCIIString = System.Text.Encoding.UTF8.GetString([Byte])
        MsgBox(MyASCIIString)

30. ASCII To ROT13 and Vice Versa - encrypts to/or decrypts from ROT13

Code:
'/ENC
 Dim MyString As String = "Hello, world"
        Dim EncOrDec As New StringBuilder
        Dim CheckCharIndex As Integer
        Dim CharIndex As Integer

        For Each xChr As Char In MyString

            If (Not Char.IsLetter(xChr)) Then
                EncOrDec.Append(xChr)
                Continue For
            End If

            CheckCharIndex = Asc("a") - (Char.IsUpper(xChr) * -32)
            CharIndex = ((Asc(xChr) - CheckCharIndex) + 13) Mod 26

            EncOrDec.Append(Chr(CharIndex + CheckCharIndex))
        Next
        MsgBox(EncOrDec.ToString())

'/DEC
  Dim MyString As String = "Uryyb, jbeyq"
        Dim EncOrDec As New StringBuilder
        Dim CheckCharIndex As Integer
        Dim CharIndex As Integer

        For Each xChr As Char In MyString

            If (Not Char.IsLetter(xChr)) Then
                EncOrDec.Append(xChr)
                Continue For
            End If

            CheckCharIndex = Asc("a") - (Char.IsUpper(xChr) * -32)
            CharIndex = ((Asc(xChr) - CheckCharIndex) + 13) Mod 26

            EncOrDec.Append(Chr(CharIndex + CheckCharIndex))
        Next
        MsgBox(EncOrDec.ToString())