Operators in Visual Basic
Operators are special symbols that perform operations on one or more values (operands). Visual Basic .NET supports a rich set of operators for various purposes, including arithmetic, comparison, logical operations, and assignments.
Arithmetic Operators
These operators are used to perform mathematical calculations.
| Operator | Description | Example |
|---|---|---|
+ |
Addition | Dim sum As Integer = 5 + 3 ' sum will be 8 |
- |
Subtraction | Dim difference As Integer = 10 - 4 ' difference will be 6 |
* |
Multiplication | Dim product As Integer = 6 * 7 ' product will be 42 |
/ |
Division (returns a floating-point result) | Dim result As Double = 10 / 4 ' result will be 2.5 |
\ |
Integer Division (discards the fractional part) | Dim quotient As Integer = 10 \ 4 ' quotient will be 2 |
Mod |
Modulo (returns the remainder of a division) | Dim remainder As Integer = 10 Mod 4 ' remainder will be 2 |
^ |
Exponentiation | Dim power As Integer = 2 ^ 3 ' power will be 8 |
Comparison Operators
These operators are used to compare two values. They return a Boolean value (True or False).
| Operator | Description | Example |
|---|---|---|
= |
Equal to | If x = 5 Then ... |
<> |
Not equal to | If name <> "Admin" Then ... |
< |
Less than | If age < 18 Then ... |
> |
Greater than | If score > 90 Then ... |
<= |
Less than or equal to | If count <= 10 Then ... |
>= |
Greater than or equal to | If total >= 100 Then ... |
Is |
Checks if two object references point to the same object | If obj1 Is obj2 Then ... |
IsNot |
Checks if two object references point to different objects | If obj1 IsNot obj2 Then ... |
Like |
Performs pattern matching on strings | If name Like "A*" Then ... |
Logical Operators
These operators combine Boolean expressions.
| Operator | Description | Example |
|---|---|---|
And |
Logical AND (returns True if both operands are True) | If isLoggedOn And hasPermission Then ... |
Or |
Logical OR (returns True if at least one operand is True) | If isSunday Or isHoliday Then ... |
Xor |
Logical XOR (returns True if exactly one operand is True) | If isMale Xor isFemale Then ... |
Not |
Logical NOT (reverses the Boolean value of the operand) | If Not isComplete Then ... |
AndAlso |
Short-circuiting AND (evaluates the second operand only if the first is True) | If number > 0 AndAlso (10 / number) > 1 Then ... |
OrElse |
Short-circuiting OR (evaluates the second operand only if the first is False) | If errorOccurred OrElse (retryCount < 3) Then ... |
Assignment Operators
These operators assign a value to a variable.
| Operator | Description | Example |
|---|---|---|
= |
Assigns the value of the right operand to the left operand | x = 10 |
+= |
Adds the right operand to the left operand and assigns the result | x += 5 ' Equivalent to x = x + 5 |
-= |
Subtracts the right operand from the left operand and assigns the result | x -= 3 ' Equivalent to x = x - 3 |
*= |
Multiplies the left operand by the right operand and assigns the result | x *= 2 ' Equivalent to x = x * 2 |
/= |
Divides the left operand by the right operand and assigns the result | x /= 4 ' Equivalent to x = x / 4 |
\= |
Performs integer division and assigns the result | x \= 2 ' Equivalent to x = x \ 2 |
&= |
Concatenates the right operand to the left operand and assigns the result | myString &= " World" ' Equivalent to myString = myString & " World" |
String Concatenation Operator
The & operator is used to combine strings.
| Operator | Description | Example |
|---|---|---|
& |
Concatenates two strings | Dim greeting As String = "Hello" & " " & "World" ' greeting will be "Hello World" |
Other Operators
Visual Basic .NET also includes other useful operators.
-
TypeOf...IsOperatorChecks if an object is of a specific data type.
Dim obj As Object = "Hello" If TypeOf obj Is String Then Console.WriteLine("obj is a String.") End If -
AddressOfOperatorReturns a delegate pointing to a procedure or function.
Dim myDelegate As EventHandler = AddressOf Button1_Click -
NewOperatorCreates a new instance of a class or structure.
Dim myObject As New MyClass() -
Function()andSub()(Lambda Expressions)Used to create anonymous functions.
Dim square = Function(x As Integer) x * x Dim result = square(5) ' result will be 25
Note: Operators have an order of precedence, which determines the order in which operations are performed in an expression. Parentheses can be used to override this order.
Tip: Using `AndAlso` and `OrElse` can improve performance by preventing unnecessary evaluation of expressions, especially when dealing with potentially null values or expensive operations.