VB.NET String

In VB.NET, string is a sequential collection of characters that is called a text. The String keyword is used to create a string variable that stores the text value. The name of the string class is System.String that contains the various function of string.

Declaration and Initialization of String

The following are the different ways to declare and initialize the string variable using the String keyword in the VB.NET programming language.

'Declaration of the String variable
Dim str As String
Dim abc As String

' Initialization of String variable
Dim str As String = "Welcome to JavaTpoint."
Dim str1 As String = "Hello World!"

' Initialize a null string
Dim str2 As String = Nothing

' Initialization of an empty string
Dim name As String = String.Empty 

' Creating a String from char
Dim letter As Char() = {"H", "E",  "L", "L", "O" }

In the above declaration of string, we have defined the string variable with string keyword and initialize string variable with value based on our requirements.

Creating a String Object

There are different ways to create a string object in the String.

To use a String class constructor.
By using the property or calling method to return a string.
Use a string literal to define a string variable.
Use a String concatenation operator (+).
By using a formatting function to convert a value or object into the string representation of the object.

Let's create an example to demonstrates the uses of String objects.

String_object.vb

Imports System
Module String_object
    Sub Main()
        Dim str, str2, fullname, data As String
        str = "Hello"
        str2 = "World!"
        fullname = str + " " + str2
        Console.WriteLine(" Message is {0}", str)
        Console.WriteLine(" Message is {0}", str2)
        Console.WriteLine(" Fullname is {0}", fullname)

        ' By using string constructor
        Dim str3 As Char() = {"H", "e", "l", "l", "o"}
        data = New String(str3)


        Console.WriteLine(" Your message is {0}", data)

        ' Use of returning string
        Dim arr() As String = {" Hello", "Welcome", "to", "JavaTpoint"}
        Dim msg As String = String.Join(" ", arr)
        Console.WriteLine(" You have defined these parameters as string array {0}", msg)

        'Use of Formatting method to convert a value to the string
        Dim time As DateTime = New Date(2020, 6, 18, 18, 48, 2)
        Dim sentmsg As String = String.Format(" Your message has been successfully sent at {0:t} on {0:D}", time)
        Console.WriteLine(" Your text is that {0}", sentmsg)
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

Immutable string object

In VB.NET, the string object is immutable. It means that once we have created a string object, it cannot be modified during its execution. And if we modified an existing value in a string object through addition and subtraction, it discards the old value of instance in memory and creates a new instance to hold a new value. Furthermore, if we want to perform any operation in the String object, we must define an object every time to create a new String object. So, in that case, the string provides the System.Text.StringBuilder class to modify a string without creating a new object.

Properties of the String Class

Following are the two properties of string class:

Chars: It is used to get the character from the current string object.
Length: It is used to return the number of characters in the current string object.

Access individual characters from Strings in VB.NET

In VB.NET, we can access the individual character from the current string object with index values.

Let's write a program to access the individual characters from the string by defining an index position.

Get_Chars.vb

Imports System
Module Get_Chars
    Sub Main()
        Dim i As Integer
        ' Declaration of String variable
        Dim name As String = "Hello World!"
        Console.WriteLine(" These are Characters in Hello World! String :")
        For i = 0 To name.Length - 1 ' Count from 0 to Length - 1
            Console.WriteLine(name(i))
        Next
        Console.WriteLine("Length is {0}", name.Length) ' Use of Length Properties
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module 

Output:

In the above program, a For loop is continuously executed each element of the String variable's value is Hello World! Until the condition (name.Length -1) is reached. Here, Length function is used to count the number of characters in the string.

There are various functions of string class that helps to manipulate the string objects.

1. Compare(): It is used to compare two specified string objects, and if the string is less than another string object, it returns an integer value.

Syntax:

The returned integer value represents the relationship between two specified string objects. The following table shows the string comparison condition that returns the integer value after comparing two specified string items.

Compare String Condition	It returns an integer value
Str1 == Str2	0
Str1 > Str2	1
Str1 < Str2	-1

Example: Write a program to understand the uses of Compare() function in String Class.

String_cmp.vb

Imports System.String
Module String_cmp
    Sub Main()
        'Definition of local String variable
        Dim Str1 As String = "Hello"
        Dim Str2 As String = "Cello"
        ' Use of String.compare() function
        Console.WriteLine(" Comparison of String {0} and {1} result is {2}", Str1, Str2, String.Compare(Str1, Str2))

        Dim Sdata As String = " WELCOME"
        Dim Sdata2 As String = " Welcome"
        ' Use of String.Compare() function
        Console.WriteLine(" Comparison result of String {0} and {1} result is {2}", Sdata, Sdata2, String.Compare(Sdata, Sdata2))

        Dim Sdata3 As String = "Hello"
        Dim Sdata4 As String = "Hello"
        ' Use of String.Compare() function
        Console.WriteLine(" Comparison result of String {0} and {1} result is {2}", Sdata3, Sdata4, String.Compare(Sdata3, Sdata4))

        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above example, the string compare () method checks the values of two string variables and returns integer values.

2. Concat()

The Concat() function is used in string class to join two or more strings or append one string to the end of another string. It is useful when we need to combine two or more text to make a sentence, and it returns a new string.

Syntax:

And when we use more than three string parameters to combine, we have to define this way:

Syntax:

Public Shared Function Concat( Str1 As String, Str2 As String, Str3 As String ) As String

Let's create a program to understand the uses of the Concat() function to append or concatenate one or more strings in the VB.NET programming language.

String_concate.vb

Imports System.String
Module String_concate
    Sub Main()
        ' Definition of local variables
        Dim str As String = "Learn"
        Dim Str2 As String = " " & "VB.NET Programming Language"
        'Use of Concat() function to combine two string variable
        Console.WriteLine("Your String is {0}", String.Concat(str, Str2))

        Dim val As String = "Want to"
        Dim val2 As String = " " & "Learn String methods"
        Dim str3 As String = " " & "in VB.NET language?"
        'Use of Concat() function to combine two or more string variable

        Console.WriteLine("Your Sentence is {0}", String.Concat(String.Concat(val, val2), str3))
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above program, we used a Concat() function to combine one or more strings to return a single string.

3. Contains(): It is used to validate whether the specified text or parameter exists in the current string. If the text is existing in the string, it returns a true Boolean value; otherwise, it returns false.

Syntax:

Let's create a program to understand the uses of the Contains() function to check whether the particular string exists or not in a given string.

String_contain.vb

Imports System.String
Module String_contain
    Sub Main()
        'Definition of local variables
        Dim msg As String = "Welcome to VB.NET Language."
        Dim txt As String = "VB.NET"

        ' Use of Contains() function
        Console.WriteLine("Does {0} String Contains {1}? :{2}", msg, txt, msg.Contains(txt))

        Dim str As String = "String is the collection of characters."
        Dim strtxt As String = "Collection"

        'Use of Contains function
        Console.WriteLine("Does {0} Sentence Contains {1}? :{2}", str, strtxt, str.Contains(strtxt))

        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above program, the String Contains() function is to determine whether the given string str contains the value of strtext, and if the value exists in the str, it returns a true value; otherwise, it returns false.

4. String Copy(): In the String class, there is a Copy() function used to create a new string object with the same content or value specified in the original string.

Syntax:

Let's create a program to understand the uses of Copy() function in the VB.NET programming language.

String_copy.vb

Imports System.String
Module String_Copy
    Sub Main()
        'Declaration and Initialization of local variable
        Dim str As String = " Welcome to JavaTpoint"
        ' Use String.Copy() function
        Dim str2 As String = String.Copy(str)
        Console.WriteLine(" Text in First String is {0}", str)
        Console.WriteLine(" Copy text is {0}", str2)

        ' Use String.Copy() function
        Console.WriteLine("Text in Copy String : {0}", String.Copy(str))
        Console.WriteLine(" Does the Object reference equal? {0}", Object.ReferenceEquals(str, str2))

        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

5. CopyTo(): A CopyTo () function is used to copy the specified number of characters from the original string object.

Syntax:

Public Sub CopyTo( sourceIndex As Integer, destination As Char(), destinationIndex As Integer, count As Integer )

Create a simple program of the CopyTo() function to copy a string in the VB.NET programming language.

String_CopyTo.vb

Imports System.String
Module String_CopyTo
    Sub Main()
      ' Declaration of String variable
        Dim data As String = "Welcometojavatpoint"
' Declaration of strcpy array
        Dim strcpy(25) As Char
        Console.WriteLine("Original String is: {0}", data)
	' use CopyTo() method
        data.CopyTo(9, strcpy, 0, 10)
        Console.WriteLine("Copied character is " + strcpy)
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

6. EndsWith(): The EndsWith() function is used to check whether the text or parameter specified in the original string ended with the specified text.

Syntax:

Let's create a program to understand the uses of EndsWith() function in the VB.NET programming language.

String_With.vb

Imports System.String
Module String_With
    Sub Main()
        'Definition of String variable
        Dim str As String
        str = " VB.NET is the best programming language"
        ' Use of EndsWith() function in String Class
        If str.EndsWith("language") = True Then
            Console.WriteLine(" The String statement EndsWith 'language'")
        Else
            Console.WriteLine(" The string is not EndsWith 'Language'")
        End If
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above program, the EndsWith() function is checked whether the defined text 'language' specified in the original string object str ends with the word language.

7. Equals(): As the name defines, an Equals() function is used in the string class to determine if both string objects have the same value or not. If the value is the same, the Equals() string methods are true; otherwise, it returns false. And if both objects have null values, the Equals() function returns a true value.

Syntax:

Let's create a program to understand the uses of EndsWith() function in the VB.NET programming language.

Equal_String.vb

Imports System.String
Module Equal_String
    Sub Main()
        'Definition of local variable
        Dim str = "Welcome"
        Dim str2 = "welcome"
        'Use of Equals() function
        Console.WriteLine("Are string {0} and {1} equal? : {2}", str, str2, String.Equals(str, str2))
        Dim str3 = "Welcome"
        Console.WriteLine("Are string {0} and {1} equal? : {2}", str, str3, String.Equals(str, str3))
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above example, the String Equals() method checks whether the specified strings object is equal. If yes, it returns True value; otherwise, it returns False.

8. String Format(): The Format() function is used to replace one or more objects with the specified string object. By using the Format() function, we can insert the value of a variable into another object string.

Syntax:

Let's create a program to understand the uses of Format() function in the VB.NET programming language.

String_Format.vb

Imports System.String
Module String_Format
    Sub Main()
        ' Declaration and Represntation of Format String
        Dim rep_string As String = " Tutorial: {0}, Topic: {1}, Method Name: {2} "

        'Use of String.Format() function
        Dim spec_string As String = String.Format(rep_string, "VB.NET", "String", "Format_String")

        Console.WriteLine(" Representation of String is {0}", spec_string)
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above example, the string Format() method has replaced the format objects {0} with "VB.NET", {1} with "String" and {2} with "Format_String".

9. IndexOf(): The String IndexOf() function is used to return the index position of the first occurrence of the specified character or string in the original string object, followed by the zero (0) index. Furthermore, we can also define the starting index position of the specified character or string in the original string.

Syntax:

'Getting a Char:
Public Function IndexOf( ByVal As Char ) As Integer

'For Getting a String:
Public Function IndexOf( ByVal As String ) As Integer

'Define the starting position of the character
Public Function IndexOf( ByVal As Char, StartIndex As Integer ) As Integer

'Define the starting position of the String
Public Function IndexOf( ByVal As String, StartIndex As Integer ) As Integer

Let's create a program to understand the uses of IndexOf() function in VB.NET programming language.

indexOf_String.vb

Imports System.String
Module indexOf_String
    Sub Main()
        Dim Str As String = "JavaTpoint"
        Dim txt As String = "Welcome to JavaTpoint Site"
        ' Use of IndexOf() function to get specified character position
        Console.WriteLine(" Occurrence of character T index position {0}", Str.IndexOf("T"))

        ' Use of IndexOf() function to get the Specified String position of specified String
        Console.WriteLine(" Occurrence of String position {0}", txt.IndexOf("JavaTpoint"))

        'Starting position of p is 5
        Console.WriteLine(" Define the starting position of the Character p is {0}", Str.IndexOf("p", 5))

        'Starting position of JavaTpoint is 5
        Console.WriteLine(" Define the starting position of the String 'JavaTpoint' is {0}", txt.IndexOf("JavaTpoint", 11, 15))

        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above example, we used an IndexOf() function to get the specified position of a character or string from the original string in VB.NET programming.

10. Insert(): The Insert() function of the String class is used to insert a specified string at the specified position in the original string object.

Syntax:

Let's create a program to understand the uses of Insert() function in the VB.NET programming language.

String_Insert.vb

Imports System.String
Module String_Insert
    Sub Main()
        Dim name = " Welcome to Site"
        Dim str_name = "JavaTpoint"
        'Use of Insert() function
        Console.WriteLine(" Inserted String {0} into Original string is {1}", str_name, name.Insert(11, " JavaTpoint"))
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

11. Remove(): The remove function is used to remove or delete characters at the specified position until the end of the defined string object. Furthermore, we can use the remove () function to remove a set of characters by defining the beginning and end positions of the characters to be removed from the original string.

Syntax:

Remove Single Character
Public Function Remove( StartIndex As Integer ) As String
Set of Character
Public Function Remove( StartIndex As Integer, Length As Integer) As String 

Let's create a program to understand the uses of Insert() function in the VB.NET programming language.

String_Remove.vb

Module String_Remove
    Sub Main()
        Dim str As String = " Welcome to JavaTpoint Site"
        ' For Single Character
        Console.WriteLine(" Remove a Single character {0}", str.Remove(3))

        ' For Group of character
        Console.WriteLine(" Remove a set of character from the original String {0}", str.Remove(1, 3))
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

12. Replace(): The String Replace() function is used to replace all the occurrence of a specified character or string from the original string object and then return a new string.

Syntax:

// Get the replace char
Public Function Replace ( oldValue As Char, newChar As Char ) As String
// Get the replace String
Public Function Replace (oldValue As String, newValue As String) As String

Let's create a program to understand the use of Replace() function in the VB.NET programming language.

String_Replace.vb

Imports System.String
Module String_Replace
    Sub Main()

        Dim ch As String = "abababab"
        'Use Replace() function to replace Single Character
        Dim strchar As String = ch.Replace("a", "c")
        Console.WriteLine(" Old Value is {0}", ch)
        Console.WriteLine(" New Value is {0}", strchar)

        Dim str As String = "It's Okay not to be Okay"
        'Use Replace() function to replace String
        Dim nstr As String = str.Replace("Okay", "Fine")
        Console.WriteLine(" Old String is {0}", str)
        Console.WriteLine(" New String is {0}", nstr)

        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above example, we used a Replace() function to replace a specified character or string from the given string in the VB.NET programming.

13. Join(): As the name suggests, a Join() function is used to concatenate all the specified elements of the string array using the specified separator.

Syntax

Public Shared Function Join ( Separator As String, paramArray Value As String() ) As String

Let's create a program to understand the uses of Join() function in the VB.NET programming language.

String_Join

Imports System.String
Module String_Join
    Sub Main()
        Dim strArray() As String = {"Hello", "Welcome", "to", "JavaTpoint", "Site"}
        'Use of String.Join() function
        Dim strSep As String = String.Join("-", strArray)
        Console.WriteLine(" Join String using the Hypen: {0}", strSep)

        Dim textArray() As String = {"want to learn", "VB.NET programming Language", "?", "Join", "the JavaTpoint Site"}
        'Use the String.Join() function with Space (vbCrLf) Seperator  

        Console.WriteLine(" Text is {0}", String.Join(vbCrLf, textArray))
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()

    End Sub
End Module

Output:

In the above program of String Join() function, we used hyphen (-) and comma (,) separator to concatenates all the elements of the string array.

14. Split(): As the name suggests, the string Split() function is used to split a given string into substrings with the help of delimiters that are used to split a string in VB.NeT programming language. Furthermore, we can specify the number of characters that should be returned in the substring.

Syntax:

Public Function Split (ParamArray separator As Char() ) As String()
' Specifies the character length
Public Function Split (ByVal separator As Char(), count As Integer) As String

Let's create a program to understand the uses of the Split() function in the VB.NET programming language.

String_Split.vb

Imports System.String
Module String_Split
    Sub Main()
        Dim str As String = "Welcome-to-JavaTpoint"
        'Use of Split() function
        Dim txtArray As String() = str.Split(New Char() {"-"c})
        For i As Integer = 0 To txtArray.Length - 1

            Console.WriteLine(txtArray(i))
        Next
        Console.WriteLine(" Press any key to exit...")
            Console.ReadKey()
    End Sub
End Module

Output:

In the above example, we used a Split() function to split the given string (Welcome-to-JavaTpoint") with a separator hyphen (-), and it returns a split string as an array. And the For loop is used to display each item of an array element.

15. StartsWith(): The StartsWith() function of String class is used to determine whether the string's beginning is matched with a specified string object. If the string is matched, it returns True value; otherwise, it shows False.

Syntax:

Let's create a program to understand the uses of StartsWith() function in the VB.NET programming language.

String_StartsWith.vb

Imports System.String
Module String_StartsWith
    Sub Main()
        Dim str As String = "Welcome to JavaTpoint"
        Dim stwith As String = "Welcome"
        Dim st As String = "to"
        ' Use of StartsWith() function
        Console.WriteLine(" String is {0}", str)
        Console.WriteLine(" Does the string start with '{0}'? : {1}", stwith, str.StartsWith(stwith))
        Console.WriteLine(" Does string start with '{0}'? : {1}", st, str.StartsWith(st))
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module
Output:
 String is Welcome to JavaTpoint
 Does the string start with 'Welcome'? : True
 Does string start with 'to'? : False
 Press any key to exit...

In the above program, we used StartsWith() function to validate whether the given string starts with "Welcome". If yes, returns True; otherwise, it shows False.

16. ToLower: The ToLower function of String class is used to convert any string object into Lower Case.

17. ToUpper: The ToUpper function of String class is used to convert a string object into Upper Case.

Let's create a program to understand the uses of ToLower and ToUpper function in the VB.NET programming language.

String_cases.vb

Imports System.String
Module String_cases
    Sub Main()
        Dim str As String = "javatpoint"
        Dim txt As String = " VB.NET TUTORIAL"
        'Use ToUpper and ToLower method in String Class
        Console.WriteLine("String converted into Upper Case is {0}", str.ToUpper)
        Console.WriteLine("String converted into Lower Case is {0}", txt.ToLower)
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output:

In the above program, we used ToLower and ToUpper method in String class to convert a given string into the Upper and Lower case of the VB.NET programming.

18. Trim(): The Trim() Function is used to remove all occurrence of leading and trailing whitespace, characters and special symbols from the specified string object.

Syntax:

Public Function Trim() As String
Public Function Trim( trimChars As Char()) As String

The First Syntax of Trim() function represents that it is used to remove all whitespaces from the starting and end of the given string.

The Second Syntax represents that it is used to trim all specified characters from the starting and end of the given string object.

Let's create a program to understand the uses of the Trim() function in the VB.NET programming language.

Trim.vb

Imports System.String
Module Trim
    Sub Main()
        Dim txt As String = "   VB.NET is the       "
        Dim ttxt As String = "   Best Tutorial   "
        Console.WriteLine(" Before Trim the String {0} {1}", txt, ttxt)
        'Use of Trim() Function to remove WhiteSpace
        Console.WriteLine(" After Trimming {0} {1}", txt.Trim(), ttxt.Trim())

        'Definition of Char() Array
        Dim trimChar As Char() = {"$c", "@", "&", "#"}
        Dim str As String = "$$## VB.NET is the Best Tutorial &&&@@@"
        Console.WriteLine(" Before Trim : {0}", str)
        ' USe of Trim() function to remove character
        Console.WriteLine(" After Trim : {0}", str.Trim(trimChar))
        Console.WriteLine(" Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module

Output: