An assignment statement is a VBA statement that assigns the result of an expression to a variable or an object.
In a book I read Excel’s Help system defines the term expression as:
“Combination of keywords, operators, variables, and constants that yields a string, number, or object. An expression can be used to perform a calculation, manipulate characters, or test data.”
Much of your work in VBA involves developing (and debugging) expressions.
If you know how to create simple formulas in Excel, you’ll have no trouble creating expressions.
With a formula, Excel displays the result in a cell.
A VBA expression, on the other hand, can be assigned to a variable.
For understanding purpose, I used Excel as an example. Please don’t get confused with it.
In the assignment statement examples that follow, the expressions are to the right of the equal sign:
X = 1 X = x + 1 X = (y * 2) / (z * 2) NumberOfParts = 15 SelectObject = True
Expressions can be as complex as you need them to be; use the line continuation character (a space followed by an underscore) to make lengthy expressions easier to read.
As you can see in the VBA uses the equal sign as its assignment operator.
You’re probably accustomed to using an
equal sign as a mathematical symbol for equality.
Therefore, an assignment statement like the following may cause you to raise your eyebrows:
x = x + 1
How can the variable
x be equal to itself plus 1?
Answer: It can’t.
In this case, the assignment statement is increasing the value of
x by 1.
Just remember that an assignment uses the equal sign as an
operator, not a symbol of equality.
Operators play a major role in VBA. Besides the assignment operator i.e. equal sign (discussed in the previous topic), VBA provides several other operators.
Below table lists these operators.
|Integer division (the result is always an integer)||\|
|Modulo arithmetic (returns the remainder of a division operation)||Mod|
The term concatenation is programmer speak for “join together”.
Thus, if you concatenate strings, you are combining strings to make a new and improved string.
VBA also provides a full set of logical operators. Below table, shows some of logical operators.
|VBA’s Logical Operators|
|Operator||What is does|
|Not||Performs a logical negation on an expression.|
|And||Performs a logical conjunction on two expressions.|
|Or||Performs a logical disjunction on two expressions.|
|XoR||Performs a logical exclusion on two expressions.|
|Eqv||Performs a logical equivalence on two expressions.|
|Imp||Performs a logical implication on two expressions.|
The precedence order for operators in VBA is exactly the same as in Excel formulas.
Exponentiation has the highest precedence. multiplication and division come next, followed by addition and subtraction.
You can use parentheses to change the natural precedence order, making whatever’s operation in parentheses come before any operator.
Take a look at this code:
z = x + 5 * y
When this code is executed, what’s the value of
If you answered 13, you get a gold star that proves you understand the concept of operator precedence.
If you answered 16, read this: The multiplication operation (5 * y) is performed first, and that result is added to
If you answered something other than 13 or 16, I have no comment.
By the way, I can never remember how operator precedence works, so I tend to use parentheses even when they aren’t required.
For example, in real life I would write that last assignment statement like this:
z = x + (5 * y)
Don’t be shy about using parentheses even if they aren’t required — especially if doing so makes your code easier to understand. VBA doesn’t care if you use extra parentheses.
Next post will be about VBA Arrays.