Transcript Excel VBA Basics

Excel VBA Basics
Outline
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Excel – Basic Elements
Using Macros
Excel VBA Basics
Excel VBA Advanced
Excel – Basic Elements
Each Row is
designated by
integer number
Cell – intersection of
row and column.
In the example the
ID of the cell: B4
Column - characters
uniquely designate
each column.
Excel Basic Data Types
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Label – anything that is just a text
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Constant – any type of number
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My daughter is 3 years old!
50%, 3.5, 775$, 10, -7.8
Formula – any math equation, always
starts with an equal sign “=”
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=5+3, =45*7-3
Excel Spreadsheet Example
Using Formulas in Excel
Assignment:
Suppose, we have a class of four students
and we need to calculate an average of the
three assignments they had for each one of
them. Given the following spreadsheet:
Solution I
We have inserted
absolute constants
and invoked
AVERAGE excel
function
After update of cell “B2”
Can you see
anything wrong?
Solution II – Using Cell
References
Solution II – Using Cell
References
Now let’s add
a constant
factor! “$A$8”
Now let’s continue the
calculations… - using “copy”
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Select cell E2 and click
<Ctrl> + C
Starting from E3 and till
E5 drag the mouse and
select the needed group
of cells
Press <Ctrl> + P
That is all!
Solution II – using Excel
Graphical User Interface
2. Click this
button
1. Select a
cell to be
updated
Solution II – using Excel
Graphical User Interface
3. In the opened
dialogue select the
needed function
Solution II – using Excel
Graphical User Interface
5.Then with
mouse select the
needed cells
4. Go with
mouse to the
first argument
(here Number1)
See how we refer
to a range!
6. Finally
click “OK”
Finally,
Using “If” Expression in Excel
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=If(A2>1,”Yes”,”No”)
If it is true that the value in the cell A2
is greater then 1, then the value of
current cell is “Yes”
 Otherwise (else), the value is “No”
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Using “Sin/Cos/Tan”
Expression in Excel
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Sin, Cos, Tan formats:
for degrees formula “= sin (angle *
pi()/180)”, the argument angle is in
degrees
 for radians formula “= sin (angle)”, the
argument angle is in radians
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Formatting Cells
Formatting Cells – cont.
Adding Graphs/Charts
Outline
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Excel – Basic Elements
Using Macros
Excel VBA Basics
Excel VBA Advanced
Using Macros
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Now let’s create a simple macro that
formats a single cell
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Changes its background
Changes its font
Recording a new Macro
Recording a new Macro –
cont.
Recording the new Macro –
cont.
Working with
Excel while
recording the
macro
Finishing the Macro
Running the Macro
Running the Macro – cont.
The Output!
Looking inside the VB code of
our Macro
What does the row
mean???
Guess what does this Macro
do? What is different now?
Outline
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Excel – Basic Elements
Using Macros
Excel VBA Basics
Excel VBA Advanced
VB example – “Hello World!”
Running the Example
The Output
Creating User From
Using Toolbox
This is a label
This is a button
Using the Toolbox
select a GUI
element and by
mouse-click place it
on the frame
Adding Code to the Button
In the open
Window fill-in
the function
•The name of the method was automatically generated
•CommandButton1 – is the name of the button object
•Click – type of the event of the object
•The method will be invoked whenever user clicks on the CommandButton1
button
Do you
remember the
code?
Running the code
The Output!!
Using Combo-Box
Add Source of
range for the
combo-box
Select
The ComboBox
Add Code to the Combo Box
The output
after user
makes combo
box
selection
Outline
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Excel – Basic Elements
Using Macros
Excel VBA Basics
Excel VBA Advanced
Modules & Procedures
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Module – collection of logically related
procedures grouped together
Procedure – a group of ordered
statements enclosed by Sub and End
Sub
Function – the same as a procedure, but
also returns some value and is closed
between Function and End Function
key words
Procedure & Function
Examples
Sub ShowTime)(
Range("C1") = Now)(
End Sub
Function sumNo(x, y)
sumNo = x + y
End Function
The procedure places
the current time
inside cell C1
The function returns sum
of two input numbers,
whose values are in the
parameter variables x &
y
Calling procedures vs. calling
If there are few
functions
sumNo functions,
Sub z(a)
MsgBox a
End Sub
Sub x()
Call z("ABC")
End Sub
Sub y()
z "ABC“
End Sub
the full name of
the function is
needed
Sub ShowSum()
MsgBox _
Module1.sumNo(3,5)
End Sub
Function sumNo(x, y)
sumNo = x + y
End Function
Passing Arguments by Value
or by Reference
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Passing arguments by reference –
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Is the VBA default
Means, if any changes happened to the argument
variables, they will be preserved after the
function/procedure finishes
Passing arguments by value –
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Is possible in VBA (by explicit definition)
Means, the pre-calling state of the argument
variables will be preserved after the
procedure/function finishes
Arguments by Ref/by Val.
Examples
Sub TestPassing1()
Dim y As Integer
y = 50
AddNo1 y
MsgBox y
AddNo2 y
MsgBox y
End Sub
Sub AddNo1(ByRef x As Integer)
x = x + 10
End Sub
Sub AddNo2(x As Integer)
x = x + 10
End Sub
public Sub TestPassing2()
Dim y As Integer
y = 50
AddNo3 y
MsgBox y
End Sub
private Sub AddNo3(ByVal x _
As Integer)
x = x + 10
End Sub
Functions/Procedure Scope
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Use public to allow any module to call
the function/procedure
Use private to make limited access to
the function/procedure (only from the
owning module)
VBA Variables
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A variable is used to store temporary
information within a Procedure, Module…
A variable name
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Must start with letter and can’t contain spaces and
special characters (such as “&”, “%”, “\”)
Can’t be any excel keyword (“if”, “while”…)
Can’t have identical name to any existing class
(“Wroksheet”, “Workbook”…)
VBA Data Type
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Byte – positive integer numbers (0:255)
Integer – integers (-32,768 : 32,767)
Long – 4-byte integer
Currency – for fixed-point calculations
Single – 2-byte floating-point numbers
VBA Data Type
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Double – double-precision floating-point
numbers
Date – used to store dates and times as
real numbers.
String – contains a sequence of
characters
The Variables Advantage by
Example
In VB the end of
statement is in the end of
line.
To write the same
statement in few lines
use “_” at the end of line!
Sub NoVariable()
Range("A1").Value = _
Range("B2").Value
Range("A2").Value = _
Range("B2").Value * 2
Range("A3").Value = _
Range("B2").Value * 4
Range("B2").Value = _
Range("B2").Value * 5
End Sub
Sub WithVariable() Dim _
iValue as Integer
iValue = _
Range("B2").Value
Range("A1").Value = _
iValue
Range("A2").Value = _
iValue * 2
Range("A3").Value = _
iValue * 4
Range("B2").Value = _
iValue * 5
End Sub
Using Variables
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Declaring Variables
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Format: Dim varibaleName AS dataType
Examples:
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Dim myText As String
Dim myNum As Integer
Dim myObj As Range
The default value of
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any numeric variable is zero
any string variable – “” (empty string)
an Object variable – is nothing (still the declaration will store
space for the object!!!)
Variant “Data Type”
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In VB you don’t have to declare variable before its
usage
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You can also declare variable as “Variant”
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Then, VB will by itself declare such variable as “Variant”
Dim myVar as Variant
Variant – means that the variable may contain any
data type
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The price is very high!!! – any time VB access such
variable, it will spend time on “deciding” what is its
“current” type!
Variables Assignment
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To assign a value to a Numeric or String
type Variable, you simply use your
Variable name, followed by the equals
sign (=) and then the String or Numeric
To assign an Object to an Object type
variable you must use the key word "Set"
Variables Assignment – cont.
Sub ParseValue )(
Dim sWord as String
Dim iNumber as Integer
Dim rCell as Range
Set rCell = Range("A1")
sWord = Range("A1").Text
iNumber = Range("A1").Value
End Sub
VBA Variables Scope &
Lifecycle
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The scope & lifecycle of a variable defines the code where the variable
can be accessed and time when the stored data is kept inside the
variable
Procedure-Level
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Module-Level
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Variables defined inside procedures
Can be accessed only inside the procedure and keep their data until the
End statement of the procedure
Defined in the top of a Module
Any procedure inside the Module can access the variable
The variable retains the values unless the Workbook closes
Project-Level, Workbook Level, or Public Module-Level
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Defined as “Public” in the top of a Module
Can be accesses by any procedure in any module
The variable retains the values unless the Workbook closes
VBA Variables Scope &
Lifecycle – cont.
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Sub scopeExample()
Dim x as Integer
Procedure level variables
x=5
End Sub
Module level variables
Dim y as Integer
‘all the module procedures are here…
Project level variables
Public z as Integer
‘all the module procedures are here…
Basic Excel Classes
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Workbook: the class represents an
Excel file
Worksheet: represents a single
worksheet
Sheet: represents a single worksheet or
chartsheet
Cell: represents a single cell
VBA Entities by Example
A Current
Workbook
A Cell
A Range
E2:E5
A current
Worksheet
Excel Containers
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Workbooks: a collection of objects of
class “Workbook”
Worksheets: a collection of objects of
class “Worksheet”
Sheets: a collection of Sheet objects
Range: a range of objects of class Cell
Referencing the Objects This will take the
Examples
whole square
between the two
cells
Sub Test1()
Worksheets("Sheet1").Range("A10", "B12") =
"Hello“
Worksheets(1).Range("A13,B14") = "World!"
End Sub
Two equal ways to
refer Sheet1
The range of
two
cells
The Output
Which Workbook was
Used?
What does this procedure do?
Sub ShowWorkSheets)(
Dim mySheet As Worksheet
For Each mySheet In Worksheets
MsgBox mySheet.Name
Next mySheet
End Sub
The Output!
How many times
the user will click
on the button?
Referencing Cells
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Cells indexing format:
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Cells(row, column), where both row and column
are given as integers (starting from 1)
Cells(index) – see the next slide
Following expressions are equivalent and
refer to the cell A1 in the currently active
sheet:
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ActiveSheet.Range.Cells(1,1)
Range.Cells(1,1)
Cells(1,1)
Referencing Cells with Offset
Range(“B1:F5”).Cells(12) = “XYZ”
See how we
calculate cell 12
In the given
range!
Referencing Cells with Offset –
cont.
ActiveCell.Offset(4, 5) = 1
This is the
currently active
cell
The assignment
result
Few methods/properties of
Excel Classes
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Workbooks.Close – closes the active
workbook
Workbooks.Count – returns the number of
currently open workbooks
Range(“A1”) is the same as
Range(“A1”).Value
Worksheets(1).Column(“A:B”).AutoFit
Worksheets(1).Range(“A1:A10”).Sort_
Workbooks.Open fileName:=“Hello.xls”,
password:=“kukuriku”
Defining and Assigning a new
Object of type Range
Dim myRange as Range
Set myRange = Range(“A1:A10”)
VBA Arrays
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Suppose, we want to keep a collection
of all the books that we loan,
Or we want to keep lists of tasks for all
the days of the week
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The naïve solution is to keep a lot of
variables
Another solution is to create array keeping
the whole collection together
Declaring object of type Array
Dim LoanBooks(3)
The array declaration.
The size must be defined
here!
LoanBooks(1) = “Winnie The Pooh”
LoanBooks(2) = “Adventures of Huckleberry Finn”
LoanBook(3) = “Frankenstein”
Multidimensional Arrays
Dim WeekTasks(7,2)
WeekTasks(1,1) = “To buy milk”
WeekTasks(7,1) = “To dance”
…
MsgBox WeekTasks(1,1) & ” ” &
& vbCrLf & WeekTasks(2,1)…
What will the
code print?
WeekTasks(1,2) _
Resizing the Arrays
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There are two ways to resize the
existing array:
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ReDim LoanBooks(7) – will erase the old
values
ReDim Preserve LoanBooks(7) – will
preserve values in indexes 1-3
Upper & Lower Index Bounds
of an Array
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Dim A(1 To 100, 0 To 3, -3 To 4)
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UBound(A, 1) – will return “100”
UBound(A, 2) – will return “3”
UBound(A, 3) – will return “4”
LBound(A, 1) – will return “1”
LBound(A, 2) – will return “0”
LBound(A, 3) – will return “-3”
Write code calculating the size of each
one of the sub-arrays
VBA Control Structures - If
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If Age >= 18 Then Status = "Adult" End If
If Age >=18
Then
Status = “Adult”
Vote = “Yes”
Else
Status = “Child”
Vote = “No”
End If
VBA Control Structures - If
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If Age >= 18
Then MsgBox "You can vote"
ElseIf Age >=22 and Age < 62
Then MsgBox “You can drive”
End If
VBA Control Structures –
Select
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Select Case Grade
Case Is >= 90
LetterGrade =
Case Is >= 80
LetterGrade =
Case Is >= 70
LetterGrade =
Case Is >= 60
LetterGrade =
Case Else
LetterGrade =
End Select
"A"
"B"
"C"
"D"
“E"
VBA Control Structures –
Loops
For i = 10 to 1 Step -2
Cells(i, 1) = “AB”
Next i
i=1
Do While i =< 10
Cells(i, 1) = i
i=i+1
Loop
i=1
Do
Cells(i, 1) = i
i =i+1
Loop While i < 11
Test yourself!
What does the procedure do?
Sub CellsExample)(
For i = 1 To 5
For j = 1 To 5
Cells(i, j) = "Row " & i & " Col " & j
Next j
Next i
End Sub
References
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http://www.usd.edu/trio/tut/excel/13.html
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http://www.anthonyvba.kefra.com/index_011.htm
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Tutorial on Excel
Great place to learn VBA basics!
http://msdn.microsoft.com/enus/library/aa224506(office.11).aspx
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MSDN online help, a good place to learn about Excel
classes (their data and functions set)
Assignment #1
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Create Excel file with grades
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The data:
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Create VBA module that will calculate final grade for every student and
places it in the new column allocated to keep the final grade
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There are 4 students with ids & names
There are 4 assignments and two exams
Each student has grades for each one of the assignments and exams, the grades are
from 20 to 100
Some cell in the worksheet keeps factor of 10
20% for the assignments average and 80% - for the maximal grade of the two exams
plus factor
If the grade becomes higher than 100 – it should be 100
Create VBA that accepts a column name from user and sorts the whole file
according to the given column
Create VBA that adds additional column with grades translated to A, B, C,
D, E, F.
Next week in class I will collect your solutions
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You should submit Excel file, and three VBA modules (only hardcopy)