Multiple variables are separated by commas. Data type of the value returned by the Function procedure; may be Byte , Boolean , Integer , Long , Currency , Single , Double , Decimal not currently supported , Date , String except fixed length , Object , Variant , or any user-defined type. Any group of statements to be executed within the Function procedure. Return value of the Function. Indicates that an argument is not required.
If used, all subsequent arguments in arglist must also be optional and declared by using the Optional keyword. Optional can't be used for any argument if ParamArray is used. ByVal Optional. Indicates that the argument is passed by value. ByRef Optional. Indicates that the argument is passed by reference.
ByRef is the default in Visual Basic. ParamArray Optional. Used only as the last argument in arglist to indicate that the final argument is an Optional array of Variant elements. The ParamArray keyword allows you to provide an arbitrary number of arguments. Name of the variable representing the argument; follows standard variable naming conventions.
Data type of the argument passed to the procedure; may be Byte, Boolean, Integer, Long, Currency, Single, Double, Decimal not currently supported Date, String variable length only , Object, Variant, or a specific object type. If the parameter is not Optional, a user-defined type may also be specified. Any constant or constant expression.
Valid for Optional parameters only. If the type is an Object, an explicit default value can only be Nothing. Remarks If not explicitly specified by using Public, Private, or Friend , Function procedures are public by default. If Static isn't used, the value of local variables is not preserved between calls. The Friend keyword can only be used in class modules. This method is based on a curious behaviour of XL97 : assume that an open workbook contains a function called "Myfunc".
But if you call it with the function wizard, it displays the informations of After further experimenting, I've noticed also that you must declare the VBA functions "Private" in order to remove them from the default "user-defined" category otherwise, they would appear twice in the wizard. This method is just a funny work-around. However, if the alias name e. For example, you can not name the function ABC as it also refers to a cell in Excel worksheet.
If you do this, Excel would give preference to the in-built function. You can use an underscore if you want to separate words. The function name is followed by some arguments in parenthesis. These are the arguments that our function would need from the user.
In our example, there is only one argument — CellRef. If you have more than one arguments, you can specify those in the same parenthesis — separated by a comma. We will see later in this tutorial on how to use multiple arguments in a user-defined function.
This would tell VBA that the result of the formula would be of the String data type. While I can use a numeric data type here such as Long or Double , doing that would limit the range of numbers it can return. Hence I have kept the function output data type as String.
The second line of the code — the one in green that starts with an apostrophe — is a comment. When reading the code, VBA ignores this line.
You can use this to add a description or a detail about the code. This is the variable where we store the value of the length of the string that is being analyzed by the formula. The fourth line declares the variable Result as a String data type. This is the variable where we will extract the numbers from the alphanumeric string. Sixth, seventh, and eighth lines are the part of the For Next loop.
The loop runs for as many times as many characters are there in the input argument. The second last line of the code assigns the value of the result to the function. The last line of the code is End Function. This is a mandatory line of code that tells VBA that the function code ends here. The above code explains the different parts of a typical custom function created in VBA. In the following sections, we will deep dive into these elements and also see the different ways to execute the VBA function in Excel.
Arguments in a User Defined Function in VBA In the above examples, where we created a user-defined function to get the numeric part from an alphanumeric string GetNumeric , the function was designed to take one single argument. In this section, I will cover how to create functions that take no argument to the ones that take multiple arguments required as well as optional arguments. These functions are not dependent on any input arguments. You can create such similar function in VBA as well. Below is the code that will give you the name of the file.
If the file has been saved, it returns the name with the file extension, else it simply gives the name. The above has one issue though. Normally a function refreshes whenever there is a change in the input arguments. To make the formula recalculate whenever there is a change in the worksheet, you need to a line of code to it.
Name End Function Now, if you change the workbook name, this function would update whenever there is any change in the worksheet or when you reopen this workbook. Creating a Function in VBA with One Argument In one of the sections above, we have already seen how to create a function that takes only one argument the GetNumeric function covered above. Function created with the below code would convert the referenced text into uppercase. Now we already have a function for it in Excel, and this function is just to show you how it works.
It then assigns the value to the function ConvertToUpperCase. Volatile part here. As soon as the argument changes, the function would automatically update.
It takes two arguments — the cell reference that has the text string, and the delimiter. Note that for each argument, you can specify a data type. When you use the above function in the worksheet, you need to give the cell reference that has the text as the first argument and the delimiter character s in double quotes as the second argument. This position is then used to extract all the characters before the delimiter using the LEFT function.
Finally, it assigns the result to the function. This formula is far from perfect. For example, if you enter a delimiter that is not found in the text, it would give an error.
If you enter the text from which you want to extract the part before the delimiter directly in the function, it would give you an error. Go ahead.. If you want the function to have the flexibility to accept direct text input or cell references from the user, you need to remove the data type declaration. This would end up making the argument as a variant data type, which can take any type of argument and process it.
An optional argument, as the name suggests, is optional to specify. But optional arguments are not useless. They allow you to choose from a range of options. Remember that the optional arguments must always come after all the required arguments.As a general rule, the Insert Function dialog displays the description of the function that is currently selected in Select a function list box. If you are using Excel or 97 you won't notice much difference, and I'll mention anything that's significant. Advantage 2: You can, slightly, simplify your formulas whenever you're using VBA functions that aren't stored in the same Excel workbook you're working in. To save the user having to enter two arguments we could let them enter just the Length and have the function use that value twice i. Instead, you can use the Array function in VBA. There's not an application. I may cover conditional formatting in future Excel tutorials. Friend Optional. Name of Elisabeth rieper thesis sentence Function; follows standard variable naming conventions. List of variables representing arguments that are passed to. Dashes should be limited to the insertion of an. This applies even if, as in the case above, you're assigning a description for a single argument.
If it's not, you can always open a user form and go to town. A Private scope means that the function is available only in the module in which it exists. When you use the above function in the worksheet, you need to give the cell reference that has the text as the first argument and the delimiter character s in double quotes as the second argument. The above steps would insert the function in the worksheet. Here in the UK fuel is sold in litres. Many global Universities and institutes offer the BBA program.
Step 3: The Squared function receives the argument of If you use an earlier version of Excel, argument descriptions are not displayed.
If your procedure refers to an undeclared variable that has the same name as another procedure, constant, or variable, it is assumed that your procedure refers to that module-level name. This word tells VBA that our code is a function and not a subroutine. A Function procedure is a VBA code that performs calculations and returns a value or an array of values. Public is the default scope of VBA functions. Method 2: Using The Application.
Run method is the macro to run Squared in the case above. Go ahead..
Go to the File tab and click on Save As. When reading the code, VBA ignores this line. Volatile part here. You can make this more robust by taking only specific values as arguments and showing an error in rest of the cases as shown in the below code.
As I understand the method, each UDF has to be "registered over" a different function from the library.
This is a mandatory line of code that tells VBA that the function code ends here. Find out how to do this in the tutorial Build an Excel Add-In. Once you've entered the appropriate name, click on the Options button located on the right side of the Macro dialog. This may change in the future.
The Application. The main use of the Application. Alternatively you can create your own add-in containing one or more functions that you can install into Excel just like a commercial add-in. The main exception to this rule are VBA functions that are defined as Private. Scenario 2: When declaring arguments for an Excel VBA Function, you can also use the As keyword and Type statement for purposes of determining its data type. You can also use the variant data type here.
You need to place the below code in a module in the VB Editor.
Using the Private keyword is useful when you create VBA Function procedures that aren't designed to be used in formulas. But I don't want to see a number, I want to see "Thursday". Functions are organized in different categories, such as Financial, Text and Logical.
Indicates that the Function procedure's local variables are preserved between calls.