Operators are used to assign or compare values. They consist of a single symbol or keyword and are usually sandwiched between a left and a right value. For example:
right = left.
Operators are intrinsic to the language (such as
=), and not functions such as those provided by System.Math.
Comparison operators compare two values and return to you a boolean (
False) as the result.
If leftValue = rightValue Then...
If leftValue <> rightValue Then...
If leftValue < rightValue Then...
Greater Than Or Equal
If leftValue =< rightValue Then...
If leftValue > rightValue Then...
Less Than Or Equal
If leftValue => rightValue Then...
|Characters in the Pattern||Matches in the String|
|?||Any single character|
|*||Zero or more characters|
|#||Any single digit (0 - 9)|
|[charlist]||Any single character in charlist|
|[!charlist]||Any single character not in charlist|
If string Like pattern Then ...
There is a single assignment operator in VB.
Dim value = 5
Watch out for assignment vs. equality comparison.
Dim result = leftValue = rightValue
In this example you can see the equal sign being used as both a comparison operator and an assignment operator, unlike other languages. In this case,
result will be of type
Boolean and will contain the value of the equality comparison between
If you have the following variables
Dim leftValue As Integer = 5 Dim rightValue As Integer = 2 Dim value As Integer = 0
Addition Performed by the plus sign +.
value = leftValue + rightValue 'Output the following: '7
Subtraction Performed by the minus sign -.
value = leftValue - rightValue 'Output the following: '3
Multiplication Performed by the star symbol *.
value = leftValue * rightValue 'Output the following: '10
Division Performed by the forward slash symbol /.
value = leftValue / rightValue 'Output the following: '2.5
Integer Division Performed by the backslash symbol \.
value = leftValue \ rightValue 'Output the following: '2
Modulus Performed by the Mod keyword.
value = leftValue Mod rightValue 'Output the following: '1
Raise to a Power of Performed by the ^ symbol.
value = leftValue ^ rightValue 'Output the following: '25
These are the bitwise operators in VB.NET : And, Or, Xor, Not
Example of And bitwise operation
Dim a as Integer a = 3 And 5
The value of a will be 1. The result is obtained after comparing 3 and 5 in binary for. 3 in binary form is 011 and 5 in binary form is 101. The And operator places 1 if both bits are 1. If any of the bits are 0 then the value will be 0
3 And 5 will be 011 101 --- 001
So the binary result is 001 and when that is converted to decimal, the answer will be 1.
Or operator places 1 if both or one bit is 1
3 Or 5 will be 011 101 --- 111
Xor operator places 1 if only one of the bit is 1 (not both)
3 Xor 5 will be 011 101 --- 110
Not operator reverts the bits including sign
Not 5 will be - 010
String concatenation is when you combine two or more strings into a single string variable.
String concatenation is performed with the & symbol.
Dim one As String = "Hello " Dim two As String = "there" Dim result As String = one & two
Non-string values will be converted to string when using &.
Dim result as String = "2" & 10 ' result = "210"
Always use & (ampersand) to perform string concatenation.
DON'T DO THIS
While it is possible, in the simplest of cases, to use the + symbol to do string concatenation, you should never do this. If one side of the plus symbol is not a string, when Option strict is off, the behavior becomes non-intuitive, when Option strict is on it will produce a compiler error. Consider:
Dim value = "2" + 10 ' result = 12 (data type Double) Dim value = "2" + "10" ' result = "210" (data type String) Dim value = "2g" + 10 ' runtime error
The problem here is that if the
+ operator sees any operand that is a numeric type, it will presume that the programmer wanted to perform an arithmetic operation and attempt to cast the other operand to the equivalent numeric type. In cases where the other operand is a string that contains a number (for example, "10"), the string is converted to a number and then arithmetically added to the other operand. If the other operand cannot be converted to a number (for example, "2g"), the operation will crash due to a data conversion error. The
+ operator will only perform string concatenation if both operands are of
& operator, however, is designed for string concatenation and will cast non-string types to strings.