MA3696 Lecture 9

LECTURE 9

Range objects
User-Defined
Functions

SUMMARY
Range objects
Obtaining a range using the RefEdit control
User-Defined Functions
 Without arguments

 With arguments
 Variables, constants, arrays and range objects

RANGE OBJECTS

A cross
between a
named range
and an array

RANGE OBJECTS
Range objects are an alternative to using arrays
and named ranges.

Range objects are preferred when:
 You are using the RefEdit control to allow users to select
data for a program.
 You are creating user defined functions which you want to
use within Excel worksheets (as opposed to using them
solely within your code).
 You are creating an Excel add-in and don’t want to clog up
the user’s workbook with range names.

DECLARING A RANGE OBJECT
A Range is a data type. So we declare a range
object as:
Dim rangeObj as Range
 Where rangeObj is the name you want to assign to the
range object

Assign a range object a range within a procedure:
Set rangeObj = Range

Set rangeObj = Range(“RangeName”)

 Where Range is a range in Excel and RangeName is a
named range in Excel.

 For example,
Set stockRange = Range(Cells(1,1), Cells(1,25))
Set stockRange = Range(“StockPrices”)

METHODS APPLIED TO RANGE OJBECTS
You can do nearly everything the same as a range
or named range in Excel. For example:
 Count rows or columns
rangeObj.Rows.Count

rangeObj.Columns.Count

 Refer to cells within the range
rangeObj.Cells(i, j).Value

REFEDIT CONTROL

Letting the
user select
the range of
data

REFEDIT
RefEdit is a UserForm control:

Allows user to select a range in Excel
Set this selection as a range object in your code
Set rangeObj = Range(RefEdit.Value)

 Where RefEdit is the (Name) of the control

Then use the range however you need to
 In a built-in function
 In a user defined function
 In place of a named range

EXERCISE 1. REFEDIT
Open Lecture 9 Student Example.xlsm
Open UserForm2
In the sub for the command button code the
following:
 Declare a range object called userSelect
 Set this range object equal to the value of the RefEdit
control
 Test that the works by outputting the range object to some
cells
 Use the .Columns.Count and .Rows.Count property to assist you
 Start the output in Cells(1,6) of Sheet 1
 Remember, to ‘copy’ or ‘output’ you just need to set the two
ranges equal to each other
 (make sure to put .Value at the end of each range)

USER DEFINED
FUNCTIONS

Create a
function in
VBA

WHAT IS A USER DEFINED FUNCTION?
Designed/created by YOU, the USER
 Similar to an Excel built-in function

Returns a value: number, text, True/False
Always goes into a Module

(not a UserForm module)

 Private Function – Only used in the module it’s in
 Public Function – Used in any module or in Excel

Can be executed in two ways:
 Called from within a Sub Procedure in VBA, OR
 Used from an Excel worksheet:
 Click on a cell, type =, then the name of your function

FUNCTION DOS AND DON’TS
Functions only do calculations
Functions DO NOT output to cells or userforms
 Do not put commands to write to cells in your function
 Do not put commands to write to userform controls in your
function

A Sub procedure performs a series of actions
 Call your function from a Sub and write the result to cells
or userforms from your Sub

ARGUMENT . AN EXAMPLE USING THE SUM FUNCTION.

This is called the ARGUMENT.
 Apply an operation to the argument and output the result
 For SUM(), it specifies what this function should sum
 In this case, we are specifying an array/range

User defined functions can have arguments too

ARGUMENT . WHEN IS IT NEEDED?
 The function operates on an argument to return a
value.

1 or more numbers

1 or more arrays/ranges

1 number

 Some functions can return a value without
operating on a variable.
NO argument needed

EXAMPLE 1. MULTIPLY 2 NUMBERS
Remember
Functions go in Modules!

Requires 2 variables as the argument
(because I want it to multiply 2 numbers together)
I’ve named them x & y


MUST assign each argument a data type

The Function itself MUST be assigned a value
WITHIN the Function
If you don’t, it will NOT return a value

USE YOUR FUNCTION IN EXCEL
Use your function like a built-in Excel function
• Type = then the name of the
User-Defined function.
• Select the function from the
list.

• Select/Enter the arguments.
• Separate the arguments
with a comma.

EXERCISE 2. CREATE AN ADD FUNCTION
Open Lecture 9 Student Example.xlsm
Open Module1
Insert a function called Add2numbers
 Give this function 2 arguments, x and y
 Write code so that this function adds the value of x and y

Test your code in an Excel worksheet – does it
work?

CALLING FUNCTIONS FROM A SUB

The name of the
Function

CALLING FUNCTIONS FROM A SUB

This function
needs 2
arguments.

EXERCISE 3. CALLING FUNCTIONS

Type this code and run the
UserForm.
Does it work (numbers only)?

EXAMPLE 2. AVERAGE OF AN ARRAY

The name of
the Function


The argument
is an array

Any array we send to
this function will be
called array1 within
the function


The number of rows
in array1() is not
known in the function

Ubound(array1) returns the
number of rows in array1


The Function is
given a value
within the
Function

We can’t use it like a built-in function because the
argument is an array.

Call it from a Sub procedure

CALL A FUNCTION FROM A PROCEDURE

FUNCTION

V

SUB

PROCEDURE

Function procedures
 Used to return a value

Sub procedures
 Use to run a series of commands
 Does NOT return a value

For example,
 If you want to output the result of a calculation in a cell
 Do the calculation in a function
 In a Sub Procedure, output that function to a cel l

Let the cells =
the value of the
function within
the Sub

EXERCISE 4. FUNCTIONS USING ARRAYS
Open Module2
Insert a function called AverageArray2D
Inside this function write code to find the average
of a 2D array.
 You can start with the code for the 1D array and just
modify it.
 The code to calculate the number of columns in an array is
UBound(arrayName, 2)
 Recall the code to calculate the number of rows in a array is
Ubound(arrayName)

 To check that your code works,
 modify Sub MainSub() so that you read in a 2D array from Excel
(use the first 2 or 3 columns – it’s up to you)
 Output AverageArray2D from a MsgBox in Sub MainSub()

EXAMPLE 3. SUM A RANGE OBJECT
Insert a function called SumOfRange
In this function add together all elements of the
range:
Range object
Count the number of rows
and cols for the loops

Use a nested loop
because you have rows
and columns of data

Use .Cells() just like
with a named range

Test this function in an Excel Worksheet

EXERCISE 5. FUNCTIONS USING RANGES
Open Module2
Insert a function called AverageOfRange
 Write code to calculate the average
 All you really need to do is modify one of your previous functions

Test your function in Excel – make sure it works

CALLING A SUB FROM WITHIN ANOTHER SUB
Very similar to calling a Function
Just write Call followed by the name of the Sub

For Example
If I had a Sub Procedure called EnableControls()
and wanted to call it from within a different Sub,
I’d write:
Call EnableControls

If the sub has arguments, then write them in
brackets, just like for a function

USING SUB PROCEDURES
Use Sub procedures for
 Tasks you want to repeat in your code

For Example
Enable textboxes
Call this sub from within another procedure

 Breaking a large chunk of code into smaller bits

For Example

 Breaking a large chunk of code into smaller bits

Using Subs in this way is ‘good practice’, but not
obligatory.

LEARNING OUTCOMES
You are ready to move on when…
 LO35: You can declare and assign a range to a range object.
You also understand when and why a range object would
be used in place of a named range or array.
 LO36: You can describe what the RefEdit tool is used for. In
addition, you can assign the value of the RefEdit tool to a
range object.
 LO37: You can describe the difference between a Sub
procedure and Function procedure. Further, you can
define what arguments are in relation to functions.
 LO38: You can write and read functions with and without
arguments (to a reasonable standard). In addition, for
functions with arguments you understand the difference
between using an array, variable or range object and can
apply that knowledge in practice.

MA3696 Lecture 9

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MA3696 Lecture 9