EXCEL WORKSHOP IIIINTRODUCTION TO MACROS AND VBA PROGRAMMING

TABLE OF CONTENTS

1. What is VBA?

2. Safety First!

1. Disabling and Enabling Macros

3. Getting started

1. Enabling the Developer tab

4. Basic VBA

1. Hierarchy

2. Properties & Methods

3. Variables

5. Macro Recorder

TABLE OF CONTENTS

6. Hello World

1. MsgBox

2. OnLoad

7. Buttons

8. Reactions

9. Arrays

10. Example: AddOneYear() to a development triangle

1. Loops / Conditional Statements

2. Custom functions

WHAT IS VBA?

VBA stands for Visual Basic for Applications

Closely related to Microsoft’s Visual Basic

VB is very archaic and now retired

VBA an Object-based Language

Similar to object-oriented languages (C++, Java)

You’ll see variables, for-loops, functions, etc.

Excel workbooks that contain macros are .xlsm files

Normal workbooks are .xlsx

We use VBA to make repetitive or complex jobs easier

SAFETY FIRST!

By default, macros are disabled with notification

Potentially malicious code can run

For example, endless MsgBoxes

You need to enable macros when opening a .xlsm workbook

Only enable macros from sources you trust

Access Macro Settings:

File > Options > Trust Center > Trust Center Settings > Macro Settings

GETTING STARTED

Enable the Developer tab

Right click on the ribbon > Customize ribbon > Check-mark the developer tab

Open the VBA Editor

Click Developer tab > Visual Basic

Or use Alt+F11

The Editor is where you edit VBA modules

Modules consists of Sub procedures and Function procedure

BASIC VBA: HIERARCHY

VBA is object-based

Objects include Workbooks, Worksheets, Cells, and Variables

Objects are organized into a hierarchy:

Application.Workbooks("Book1.xlsx")

Application.Workbooks("Book1.xlsx").Worksheets("Sheet1")

Application.Workbooks("Book1.xlsx").Worksheets("Sheet1").Range(“A1”)

Excel uses the active objects if you omit references

Range(“A1”) refers to Cell A1 on the active worksheet in the active workbook

You can also access cells using column and row number

Cell A2 is Cells(1,2) or Range(“A2”)

BASIC VBA: PROPERTIES & METHODS

Objects have properties

Range("A1").Value 'Returns the content of Cell A1

Range("A1").Width 'Returns the width of the Cell A1

Range("A1").Font

Objects have methods

Range("A1").ClearContents

Workbook("Book1.xlsx").Close

Range("A2:A3").Copy _ 'Underscore indicates continuation to next line

destination:= Range("B2")

'destination is a parameter of the Copy method

BASIC VBA: VARIABLES

Declaring a variable using the keywords Dim and as

Dim myInt as Integer 'Allocates 2 bytes of memory for an Integer

myInt = 100 'Sets the value of the variable

Other commonly used data types include

Double (8 bytes) Used for floating-point numbers (decimals)

Fixed-length String (Size depends on number of characters) Used for text

Dim myString As String * stringLength

Variable-length String (10 more bytes than a Fixed-length String)

Dim myString As String

Boolean (2 bytes ) True (-1) or False (0)

Variant (16 bytes) Can store any kind of data. Slower to process and makes code hard to read.

THE IMMEDIATE WINDOW

Public Sub PrintValue()

Debug.Print "Hello" 'Prints to the immediate window

Debug.Print x 'Prints the value of the variable x

End Sub

• Very useful feature in the VBA Editor

• Open with Ctrl+G or View > Immediate Window

• You can ask questions in the Immediate Window

?Worksheets.Count

?Range("B2").Value

• Debug.Print is useful when you are debugging

RECORDING MACROS

A lot of people learn to code in VBA by recording actions in Excel and reading the

code for those actions.

Step 1: Start recording

Developer > Code > Record Macro

Step 2: Do stuff in your workbook

Step 3: Stop recording

Developer > Code > Stop Recording

Step 4: Read the code in the Editor

Developer > Code > Visual Basic (or Alt+F11)

RECORDING MACROS: EXAMPLE

You have data on ALL Major League Baseball teams’ performance from the past decades

We ask: How has the win-percentage of 1st-place teams in the NL West Division changed over the years?

Generate a linear regression line.

1. Go to the sheet “Using Macro Recorder”

2. Start recording: Developer > Code > Record Macro

3. Activate filtering: Data > Sort & Filter > Filter

4. Filter Column D for NL West

5. Filter Column K for 1st Place Finishes

6. Select Columns B (Year) and I (Win Percentage)

7. Insert > Scatterplot

8. Right-click the plus-sign (+) for Chart Elements, then add Trendline

9. Go to “More Options” for the Trendline and Display Equation and R²

10. Stop recording

RECORDING MACROS: EXAMPLE

Go to Developer > Visual Basic to review the code in the Editor

Sub Macro1()

Selection.AutoFilter 'Activates Filtering

ActiveSheet.Range("$A$1:$V$2565").AutoFilter _

Field:=4, _ 'Filters the 4th column of Selection

Criteria1:="NL West" 'For those in the NL West

ActiveSheet.Range("$A$1:$V$2565").AutoFilter _

Field:=11, _

Criteria1:=Array( "1st of 4", … , "1st of 7"), _

Operator:=xlFilterValues

RECORDING MACROS: EXAMPLE

Range("B:B,I:I").Select

ActiveSheet.Shapes.AddChart2(240, xlXYScatter).Select

ActiveChart.FullSeriesCollection(1).Trendlines.Add

Type:=xlLinear, … ,

DisplayEquation:=0,

DisplayRSquared:=0,

Name:="Linear (W.L.)"

ActiveChart.FullSeriesCollection(1).Trendlines.Add

ActiveChart.FullSeriesCollection(1).Trendlines(2).Select

Selection.DisplayEquation = True 'Displays equation y=mx+b

Selection.DisplayRSquared = True 'Displays R-squared value

Application.CommandBars("Format Object").Visible = False 'Closes sidebar

End Sub

HELLO, WORLD

Let’s try a few different ways to display “Hello World”

Create a new module in the Project Window

Edit the name of the module in the Properties Window (F4)

Write the following code:

Option Explicit 'You must explicitly Dim new variables As a data type

Sub HelloWorld() 'Sets the content of Cell C5 to “Hello World”

ActiveSheet.Range("C5").Value = "Hello World"

End Sub

In Excel, go to Developer > Code > Macros and click HelloWorld to run

HELLO WORLD: MESSAGE BOXES

Create another module in the Project Window

Write the following code:

Option Explicit

Sub HelloWorldPopUp()

MsgBox "Hello World“ 'Generates a pop-up box

End Sub

In Excel, run this HelloWorldPopUp macro

HELLO WORLD: ONLOAD

Create another module in the Project Window

Write the following code:

Private Sub Worksheet_Activate()

MsgBox ("Thank you for coming to the workshop today!")

End Sub

Private Sub Worksheet_Deactivate()

MsgBox ("Bye, I will miss you")

End Sub

In Excel, click this sheet, and then click away to see the MsgBoxes

BUTTONS

You can create a button to run a macro when you click on it

Step 1. Draw a button.

Go to Developer > Controls > Insert > Button (Form Control)

Draw the button

Step 2. Assign a macro.

Right-click on the button > Assign Macro > New/Edit

Type the following code:

Option Explicit

Sub HelloWorld()

ActiveSheet.Range("C5").Value = "Hello World"

End Sub

REACTIONS

You can write a macro to react to a user’s action

Option Explicit

Private Sub Worksheet_SelectionChange(ByVal Target As Range)

If Selection.Count = 1 Then

If Not Intersect(Target, Range("F8")) Is Nothing Then

MsgBox "Hello there"

ElseIf Not Intersect(Target, Range("F10")) Is Nothing Then

MsgBox "Oopsie, wrong button"

End If

End If

End Sub

ARRAYS

An array holds a list of elements of the same data type

There are multiple ways to declare a static array.

Dim myArray(0 To 3) As Integer 'Create array with locations 0,1,2,3

Dim myArray(3) As Integer 'Defaults as 0 to 3 i.e. locations 0,1,2,3

Dim myArray(1 To 5) As Integer 'Locations 1,2,3,4,5

You can set the values of elements

myArray(3) = 97 'Sets the value of the 4th element of myArray to be 97

ARRAYS CONTD.

You can use the Array function to set the values in an array of Variants

Dim arr1 As Variant

arr1 = Array("Orange" , "Peach" , "Pear")

Dynamic Arrays do not need the size to be specified upon declaration

Dim dynArr1() As Variant 'Declares a dynamic array

ReDim dynArr(x+1) 'Sets the size of the array to x+1

ReDim Preserve dynArr(x+3) 'Extends the size of the array by 2 while preserving existing data

DEVELOPMENT TRIANGLE

The development triangle is used to project ultimate losses

The triangle below shows losses for six accident periods (2012, … , 2017)

The loss amount for each accident period is shown at various ages (months after the beginning of the

accident period)

A B C D E F G

1 12 24 36 48 72 84

2 2012 1375 1994 2532 2834 3034 3156

3 2013 1894 2746 3488 3906 4180

4 2014 2214 3210 4077 4566

5 2015 3526 5113 6493

6 2016 5571 8078

7 2017 5876

A B C D E F G

1 12 24 36 48 72 84

2 2012 1375 1994 2532 2834 3034 3156

3 2013 1894 2746 3488 3906 4180

4 2014 2214 3210 4077 4566

5 2015 3526 5113 6493

6 2016 5571 8078

7 2017 5876

DEVELOPMENT TRIANGLE

The triangle below is As of 12/31/2017.

At 12/31/2018, we need to add a row (Acc. Per. 2018) and a column (age 96)

Let’s write a macro called AddOneYear()

EXAMPLE: ADDING A YEAR TO A DEVELOPMENT TRIANGLE

Option Explicit

Sub AddOneYear()

Application … Range("B1").Select 'Begin in Cell B1 (Age 12)

Dim lastAge As Integer 'Will store the rightmost age (Age 84)

'Loop rightward across ages until the rightmost (Age 84) is found

While IsEmpty(ActiveCell) = False

lastAge = ActiveCell.Value 'Store value as lastAge found

'Select one cell to the right

ActiveCell.Offset(0, 1).Select

Wend

ActiveCell.Value = lastAge + 12 'Adds Age 96 to the right

EXAMPLE: ADDING A YEAR TO A DEVELOPMENT TRIANGLE

Range("A2").Select

Dim lastYear As Integer

While IsEmpty(ActiveCell) = False

lastYear = ActiveCell.Value

ActiveCell.Offset(1, 0).Select

Wend

ActiveCell.Value = lastYear + 1

Range("A1").Select 'Return to Cell A1

End Sub

QUESTIONS?