Excel VBA Programming - Variables and Data Types | 2 - Variable Declarations and Assignments

Summary

This lesson delves into the fundamentals of VBA programming with a focus on variables. It explains variables as placeholders for data, which can range from numbers to complex objects. The script covers variable declaration using the 'Dim' keyword, assigning data types, and the importance of variable names. It highlights the 'Option Explicit' setting for mandatory variable declaration and discusses variable scope, emphasizing the simplification variables bring to referencing and manipulating data within VBA code.

Takeaways

• 📌 Variables in VBA are placeholders for data, which can be a number, text, or an entire VBA object like a range, workbook, or worksheet.
• 🔑 The process of using a variable involves two main steps: declaration, where you inform VBA about the variable's name and data type, and assignment, where you give the variable a specific value.
• 💡 The 'Dim' keyword in VBA is short for 'Dimension' and is used to declare a variable, indicating the start of the variable declaration.
• 📝 Variable names in VBA should be descriptive, not exceed 255 characters, and cannot contain spaces, special characters, or be the same as VBA reserved keywords.
• 🚫 Variable names cannot start with a number or an underscore, and must be unique within the procedure they are declared in due to the concept of scope.
• ⚠️ 'Option Explicit' at the top of each module enforces that all variables must be declared before they are used, preventing potential errors.
• 🔢 Data types in VBA, such as 'Integer', define what kind of data a variable will store, which helps VBA allocate the appropriate amount of memory.
• 🔄 VBA is not case sensitive, meaning 'Age' and 'age' are considered the same variable, but it's best to maintain consistent casing for clarity.
• 🔄 Variables can simplify the process of referencing complex objects in VBA by using a simple name instead of a fully qualified reference.
• 🛠️ Variables can be used in operations just like plain numbers, making them versatile tools for manipulating data within a VBA program.
• 📈 The importance of variables will become more evident as programming progresses, especially when accessing and manipulating data on spreadsheets.

Q & A

What is a variable in the context of VBA programming?

A variable in VBA programming is a placeholder for a piece of data, which can be a number, text, string, or a complete VBA object such as a range, workbook, or worksheet.

Why are variables important in VBA programming?

Variables are important because they simplify the process of referencing complex objects and allow developers to avoid repeatedly writing out the same object references.

What are the two parts of a variable in VBA?

The two parts of a variable in VBA are the declaration and the assignment of a specific value.

What does the keyword 'Dim' stand for in VBA?

The keyword 'Dim' in VBA stands for Dimension, which is used to declare a variable and allocate a piece of computer memory for it.

What is the purpose of the 'Option Explicit' setting in the VBA editor?

The 'Option Explicit' setting mandates that every variable must be declared before it is assigned a value, ensuring that the program explicitly states the intention to have a variable of a certain type.

What are some restrictions on variable names in VBA?

Variable names in VBA cannot be greater than 255 characters, cannot contain spaces, mathematical symbols, punctuation characters, special characters, or be reserved VBA keywords. They also cannot start with a number or an underscore.

What is the difference between variable declaration and variable assignment in VBA?

Variable declaration in VBA is the process of telling the program that a certain variable of a specific type will be used, while variable assignment is the process of giving that variable an actual value.

What is the scope of a variable in VBA?

The scope of a variable in VBA refers to the boundary within which a variable exists. A variable only exists as long as the procedure in which it is declared is running.

Is VBA case sensitive when it comes to variable names?

No, VBA is not case sensitive. A variable with a capital letter and the same variable with a lowercase letter are considered the same in VBA.

How can you use a variable in VBA after it has been declared and assigned a value?

After a variable has been declared and assigned a value, you can reference it anywhere in the procedure's code, and it will represent the assigned value. You can also perform operations with it as you would with a plain number.

Why should variable names be descriptive in VBA?

Variable names should be descriptive to clearly indicate what the variable represents or holds, making the code more readable and easier to understand.

Outlines

00:00

📘 Understanding Variables in VBA

This paragraph introduces the concept of variables in VBA programming, emphasizing their role as placeholders for data. Variables can hold various types of data, including numbers, text, strings, and VBA objects like ranges or workbooks. The paragraph explains the benefits of using variables, such as simplifying the process of referencing objects and avoiding repetitive object references. It also outlines the two-part process of variable creation: declaration, where memory is allocated and the variable type is specified, and assignment, where a specific value is given to the variable. The importance of choosing descriptive variable names and adhering to VBA's naming conventions is highlighted, including restrictions like no spaces, special characters, or reserved keywords, and the case insensitivity of VBA variables.

05:02

📌 Variable Declaration and Assignment in VBA

The second paragraph delves deeper into the process of declaring and assigning values to variables in VBA. It explains the 'Dim' keyword, which is used to declare a variable and must precede the variable name. The paragraph also discusses the 'As' keyword, which specifies the data type of the variable, and the importance of declaring the variable type to ensure proper memory allocation. The concept of 'Option Explicit' is introduced, which requires all variables to be declared before they are used. The paragraph further explains the rules for variable naming, including the uniqueness within a procedure, the scope of variables, and the restrictions on starting variable names with numbers or underscores. It concludes with an example of assigning a value to a variable and demonstrates how variables can be used in operations and referenced in code, highlighting the flexibility and utility of variables in VBA programming.

Keywords

💡Variable

A 'variable' in the context of programming, including VBA, is a fundamental concept that refers to a storage location paired with a name, which the program can reference. It's used to hold data that can change during program execution. In the video, variables are introduced as placeholders for data such as numbers, text, or even complex objects like a range in Excel. The script illustrates variable declaration and assignment, emphasizing their role in simplifying code and referencing objects without repeatedly writing out their full reference.

💡Data

'Data' in the script represents the information that a variable can store. This can range from simple numeric values, strings of text, to more complex structures like VBA objects. The script emphasizes that variables are essential for managing data within a program, allowing developers to work with data more abstractly and efficiently.

💡Declaration

In programming, 'declaration' is the process of informing the compiler or interpreter about the existence of a variable and its data type. The script uses the term to describe the first step in using a variable, where the developer tells VBA to allocate memory for the variable and specifies its type, such as 'Integer' for whole numbers.

💡Assignment

'Assignment' refers to the action of associating a value with a variable. In the script, after a variable is declared, the next step is to assign it a specific value, like setting the variable 'age' to 26. This action links the variable name to an actual piece of data within the program.

💡Integer

An 'Integer' is a data type representing whole numbers without a fractional component. In the script, 'age' is declared as an Integer, which means it can only hold whole numbers. This is used to demonstrate how variables can store specific types of data.

💡Scope

'Scope' defines the context within which a variable is accessible. The script explains that a variable's scope is limited to the procedure in which it's declared. Once the procedure finishes executing, the variable is removed from memory, illustrating the concept of local versus global variables.

💡Option Explicit

'Option Explicit' is a directive in VBA that requires all variables to be declared before use. The script mentions this setting as a best practice to avoid runtime errors by ensuring that variables are explicitly declared, thus improving code reliability and readability.

💡Memory Allocation

'Memory Allocation' is the process of reserving a portion of a computer's memory for use by a program. In the script, when a variable is declared, VBA allocates memory to store the data that the variable will eventually hold, as demonstrated with the 'age' variable being declared as an Integer.

💡Procedure

A 'Procedure' in VBA is a set of instructions that performs a specific task. The script introduces a new procedure called 'My First Variable' to demonstrate the process of declaring and using variables within the context of a VBA procedure.

💡Case Sensitivity

'Case Sensitivity' refers to how a programming language distinguishes between uppercase and lowercase letters. The script clarifies that VBA is not case sensitive, meaning 'Age', 'age', and 'AGE' would all refer to the same variable, though it advises against using different cases for the same variable to avoid confusion.

Highlights

Variables are essential in VBA programming as placeholders for data.

Data can be a number, text, string, or a complete VBA object like a range or a workbook.

A variable name points to a specific object, simplifying object references.

The process of declaring a variable involves allocation of memory and specifying the data type.

The 'Dim' keyword is used for declaring variables in VBA.

Variable names should be descriptive and follow specific naming conventions.

Variable names cannot contain spaces, special characters, or be reserved VBA keywords.

The 'Option Explicit' setting requires all variables to be declared before use.

Variable scope is limited to the procedure in which it is defined.

Variable names must start with a letter and cannot start with a number or underscore.

Assigning a value to a variable involves using an equal sign and the desired value.

Variables can be used in operations just like plain numbers.

VBA is not case sensitive, and variable names with different casing are treated as the same.

Variables simplify the process of referencing complex objects in VBA.

Understanding variables is a foundational concept before diving into more advanced programming in VBA.

The lesson covers the importance and basics of variables, setting a foundation for further VBA programming.

Transcripts

in this lesson we'll talk about variables which  are a very important part of VBA programming  

a variable is just a placeholder for a piece of  data in our program now what do I mean by a piece  

of data well data can mean anything from a number  to a piece of text or a string to a complete VBA  

object like a range or a workbook or a worksheet  a variable is just a name that we choose as a  

developer that points to a specific object in our  program so we don't have to reference that object  

over and over and over again so if you think back  a while ago when we talked about fully qualified  

references for example when we used application  and then workbooks and worksheets to reference  

a specific range object that process of writing  out that reference can take a while to write out  

it's much easier to just write it out once and  assign that final object reference to a variable  

which again is just a placeholder name and then  reference that variable instead of writing out  

the entire object reference again so variables  are just simple simple ways that we can refer  

to something in our program without having  to remember exactly what a specific value is  

or a specific object is so let me go ahead and  create a sample variable here for you there's  

actually two parts to a variable the first is the  Declaration and the second is the assignment of  

a specific value so the Declaration which is the  first step is the part where we tell VBA that we  

want to allocate a piece of computer memory for a  variable we're going to say we're going to define  

a name here a specific variable which is just a  name and we also have to tell VBA the kind of data  

that it's going to hold so that when we assign a  value to it VBA is prepared to store or reference  

that specific kind of data so let me go ahead  and create a brand new procedure here I'm going  

to call it my first variable and as soon as I add  the parentheses and press enter VBA will complete  

the end sub so what I'm going to do here is write  out a single variable declaration because it's a  

lot to take in at first so I'm going to write it  out completely and then go through it step by step  

so here we go dim age as integer as soon as I do  a line break perfect there it is the first part  

here is the dim keyword which is actually part  of VBA it's a keyword within the language dim  

is short for Dimension and that's an old school  computer science term for variable so dim always  

has to be written before we write out any of our  variables so if we had more than one variable we  

always place the dim keyword before the actual  name so immediately after the dim keyword we write  

the name of the variable this is our own decision  this is up to the developer and ideally the name  

should describe what the variable is going to hold  so in this case I want a variable that's going to  

store my age let's say I don't want to remember  it and I just want to store it in a variable once  

so that I can always reference age later in the  program and know that it's always going to give  

me the actual numeric value of my age so age is  up to me to decide in terms of the variable name  

I've chosen age that's the second thing I put in  this sequence of four items immediately after the  

variable name I put the keyword as that also is  part of VBA and that also also must always be  

included and finally at the very end that's where  we declare the variable type this means the type  

of data that is being stored we we have as I  mentioned many different types of data we have  

integers we have strings we have complete DBA  objects we have to tell VBA in order for it to  

allocate memory exactly what we plan to store in  this variable in this case age is going to be an  

integer as a basic mathematic review an integer is  just a number without a floating Point component  

so a number without a decimal a whole number like  5 or 10 or 15. earlier on when we were looking at  

some of the configuration settings in the Visual  Basic editor we enabled an option that mandates  

that option explicit appears at the very top  of each of our modules this option explicit  

setting mandates that every variable be declared  before we actually assign it a value and when we  

when we say variable declaration that's this part  we are declaring we are telling the program as a  

statement of fact that we are going to have some  kind of variable called age in this procedure and  

that we expect age to be of an integer type a  whole number but we haven't actually assigned  

it a value yet we don't know what age is equal  to we just tell VBA to spare some memory for it  

now there are a couple restrictions that VBA  places on our variable names that I want you  

to be aware of the first is that variable names  cannot be greater than 255 characters you're  

generally not going to run into this problem with  your variable names but I did want you to be aware  

of it variable names exactly like procedure names  cannot contain spaces so if you have multiple  

words you can stick with the upper camel case  syntax which means the first letter of every word  

can be capitalized and you can use that to sort of  Mark where a new word begins but you cannot have  

actual spaces in your variable names variable  names also cannot contain mathematical symbols  

like plus or minus they cannot contain any kind  of punctuation characters like the question mark  

or the exclamation point they cannot contain  special characters like the hashtag and they  

cannot be reserved VBA keywords like sub or end or  option or explicit or worksheet so don't create a  

variable called worksheet the variable access has  to be some kind of name that isn't part of the VBA  

language the variable must also be unique in the  procedure that defines it which means we can't  

declare another variable called age in the exact  same my first variable procedure so that's going  

to trigger an error in VBA however we can have the  same variable names across different procedures  

so if I had another procedure below my second  variable and I declared a variable called age  

in there that's totally valid and age in my second  procedure can be a totally different data type the  

reason we can do this across different procedures  is because the variable has this concept of scope  

and scope refers to the Limit or the reach or  the boundary in which a variable exists and a  

variable only exists as long as the procedure  is running so every time my first variable is  

executed it's going to create a variable called  age that's going to be an integer but as soon as  

that procedure is done that variable is tossed  out of memory it doesn't exist any longer so  

whenever we run a second procedure that also has a  variable called age that second variable is simply  

going to be created from scratch and that process  continues over and over and over again finally we  

cannot start a variable name with a number or  an underscore the variable name can contain a  

number or an underscore but it cannot start with  it so the general best practice to follow is to  

start your variables with a letter and just make  it as descriptive as possible it should describe  

the actual value that it's holding so age is a  is a pretty good variable name you don't want  

something like num or num1 you don't just want  to say it's a number you want to describe what  

it actually is what it actually represents so  now that we've declared the age variable as  

a type of integer we can actually go ahead and  assign it a value the way we do that is on the  

line below we write the name of the variable this  is age this is our own custom name we're given an  

equal sign much like if we were assigning a value  to a property of an object just an equal sign and  

then on the right side we write the actual value  that we want to assign to this variable so let's  

make the age variable equal to 26. so what does  this mean well age is now a placeholder and it's  

a placeholder for a number of 26. that means that  I can reference the variable age anywhere in this  

procedures code and it will give me the value  26. it's a representative of that value it's a  

placeholder over it so for example if I wanted to  debug print rather than writing 26 I can simply  

write age and whenever VBA evaluates this it's not  going to print the literal string age rather it's  

going to say hey you have a variable here what  does that equal to oh right here it's defined  

to be 26 so I know that it's a reference to  that number so this is going to evaluate to  

26. so when I execute this procedure 26 is going  to print in my immediate window remember that age  

is a variable that represents a number but we're  not limited to Simply outputting that variable we  

can do any kind of operations that we would do  with a plain number so for example if I wanted  

message box and I want to see what my age will be  in uh four years what I can do is age plus four  

the reason I can do this is because age is just a  name for a number it represents it's a placeholder  

for the value that I assign up here so when VBA is  evaluating this it's going to substitute age for  

the value to sign up here 26 it's going to add 4  to get 30 and once it evaluates to 30 that's what  

message box is going to output for us so when I  execute this a message box with 30 is going to  

appear in the middle right here One Last Detail  VBA is not case sensitive which means a variable  

with a capital A and a variable with a lowercase  a are the exact same thing VBA will generally try  

to correct you whenever you use the wrong case so  for example if I try doing something like this if  

I try typing age with a lowercase a you can see  it's automatically going to boost it back up to  

an uppercase a because it identifies that that  variable exists but VBA is not case sensitive  

so in case of any kind of error do not declare  variables with the same name but different casing  

VBA will try to correct for it but you should  avoid it as a general practice if you want another  

variable find a completely different name to give  it that's all there is to cover in this lesson  

variables are just placeholders or names that we  assign to pieces of data in our code right now  

I'm sure you're not seeing the the big benefit of  this but rest assured variables are really helpful  

when we get to the nitty gritty of actually  accessing values on our spreadsheet manipulating  

them overwriting them variables help simplify  the process of referencing complex objects  

that's all there is to cover here and throughout  this entire section we're going to be diving a  

lot into variables and the various data types  that we can use in our code it's an important  

foundation to lay before we start diving into  the actual parts of programming in VBA itself