How to Evaluate Strings as Formulas in Microsoft Visual Basic for Applications (VBA)
Microsoft Visual Basic for Applications (VBA) allows you to work with Excel worksheet expressions and formulas by evaluating strings. This functionality can be incredibly useful for a wide range of tasks, from simple arithmetic operations to complex data manipulations. In this article, we will explore how to use the Application.Evaluate method to evaluate strings as formulas in VBA.
Using Application.Evaluate to Evaluate Strings as Formulas
Excel's Application.Evaluate function can take a string and evaluate it as a valid Excel formula. This is particularly useful when you need to compute a value from a string that contains cell references or other Excel functions. Here are some examples of how to use Application.Evaluate effectively.
Evaluating Simple Formulas
Suppose you have a string that represents a simple Excel formula, like so:
MyVar Application.Evaluate("A53")or
MyVar Application.Evaluate("5")In the first example, A53 is a cell reference. In the second, the string simply represents the number 5, which is a valid formula. The Application.Evaluate function interprets the string and returns the corresponding value. Note that the equals sign is not required within the string, as Application.Evaluate is aware of this convention.
Evaluating Arrays Using Application.Evaluate
The Application.Evaluate function can also handle arrays. Consider the following example:
RowNum 25 MyVar Application.Evaluate("A2:A"" RowNum "")This code snippet first sets the variable RowNum to 25. It then uses Application.Evaluate to generate an array from cells A2 to A25. The evaluated array is then stored in MyVar.
Mixing VBA Expressions with Worksheet Expressions
Another powerful use of Application.Evaluate is when you need to build expressions that mix VBA and worksheet expressions. For example, you can use VBA expressions to dynamically create strings that represent complex formulas involving cell references or other conditions.
RowNum 25 MyVar Application.Evaluate("SUM(A2:A" RowNum "")")This code snippet uses VBA to construct a string that represents the SUM formula over a range, and then it uses Application.Evaluate to calculate the sum.
Using Square Brackets to Evaluate Expressions
As an alternative to using the Application.Evaluate function, you can use square brackets around the expression you want to evaluate. This form of evaluation is often more concise and can be easier to read.
MyVar [VLOOKUP A2 Sheet2!A:D 3 FALSE]In this case, the expression within the square brackets is evaluated as a VLOOKUP formula. The result of the VLOOKUP is then assigned to MyVar.
Conclusion
The Application.Evaluate function in Microsoft VBA is a versatile tool that can be used to evaluate strings as formulas in various contexts. Whether you are building complex formulas dynamically or simplifying your code by evaluating string expressions, Application.Evaluate can streamline your VBA programming.
By leveraging the power of string evaluation, you can achieve more flexible and dynamic manipulation of Excel data using VBA. Experiment with different expressions and references to fully understand the capabilities of this feature.
References
For more detailed information and advanced applications, please refer to the Microsoft VBA documentation and relevant Excel function documentation.