- Think of an array in VBA array as a mini database to store and organized data (Example: student’s name, subject, and scores).
- Before you use it, you need to declare an array; with its data type, and the number of values you want to store in it.
If you want to work with large data using VBA, then you need to understand arrays and how to use them in VBA codes, and in this guide, you will be exploring all the aspects of the array and we will also see some examples to use them.
What is an Array in VBA?
In VBA, an array is a variable that can store multiple values. You can access all the values from that array at once or you can also access a single value by specifying its index number which is the position of that value in the array. Imagine you have a date with student’s name, subject, and scores.
You can store all this information in an array, not just for one student but for hundreds. Here’s a simple example to explain an array.
In the above example, you have an array with ten elements (size of the array) and each element has a specific position (Index).
So, if you want to use an element that is in the eighth position you need to refer to that element using its index number.
The array that we have used in the above example is a single-dimension array. But ahead in this guide, we will learn about multidimensional arrays as well.
How to Declare an Array in VBA
As I mentioned above an array is the kind of variable, so you need to declare it using the keywords (Dim, Private, Public, and Static). Unlike a normal variable, when you declare an array you need to use a pair of parentheses after the array’s name.
Let’s say you want to declare an array that we have used in the above example.
Steps to declare an array.
- First, use the keyword “Dim”, enter the name of the array, and type parentheses.
- Next, you need to specify the data type for the array. If you do not have any data type specified VBA will assign appropriate data type.
- After that, you need to define the number of items that you want to store in the array.
- In the end, to assign a value to an item in an array you need to use item’s index number to identify it and then assigning a value to it.
Sub vba_array_example() Dim StudentsNames(10) As String StudentsNames(0) = "Waylon" StudentsNames(1) = "Morton" StudentsNames(2) = "Rudolph" StudentsNames(3) = "Georgene" StudentsNames(4) = "Billi" StudentsNames(5) = "Enid" StudentsNames(6) = "Genevieve" StudentsNames(7) = "Judi" StudentsNames(8) = "Madaline" StudentsNames(9) = "Elton" End Sub
- In the above code, first, you have the Dim statement that defines the one-dimensional array which can store up to 10 elements and has a string data type.
- After that, you have 10 lines of code that define the elements of an array from 0 to 9.
Array with a Variant Data Type
While declaring an array if you omit to specify the data type VBA will automatically use the variant data type, which causes slightly increased memory usage, and this increase in memory usage could slow the performance of the code.
So, it’s better to define a specific data type when you are declaring an array unless there is a need to use the variant data type.
Returning Information from an Array
As I mentioned earlier to get information from an array you can use the index number of the element to specify its position. For example, if you want to return the 8th item in the area that we have created in the earlier example, the code would be:
In the above code, you have entered the value in cell A1 by using item 8 from the array.
Use Option Base 1
I’m sure you have this question in your mind right now why we’re started our list of elements from zero instead of one?
Well, this is not a mistake.
When programming languages were first constructed some carelessness made this structure for listing elements in an array. In most programming languages, you can find the same structure of listing elements.
However, unlike most other computer languages, In VBA you can normalize the way the is index work which means you can make it begins with 1. The only thing you need to do is add an option-based statement at the start of the module before declaring an array.
Now this array will look something like the below:
Searching through an Array
When you store values in an array there could be a time when you need to search within an array.
In that case, you need to know the methods that you can use. Now, look at the below code that can help you to understand how to search for a value in an array.
Sub vba_array_search() 'this section declares an array and variables _ that you need to search within the array. Dim myArray(10) As Integer Dim i As Integer Dim varUserNumber As Variant Dim strMsg As String 'This part of the code adds 10 random numbers to _ the array and shows the result in the _ immediate window as well. For i = 1 To 10 myArray(i) = Int(Rnd * 10) Debug.Print myArray(i) Next i 'it is an input box that asks you the number that you want to find. Loopback: varUserNumber = InputBox _ ("Enter a number between 1 and 10 to search for:", _ "Linear Search Demonstrator") 'it's an IF statement that checks for the value that you _ have entered in the input box. If varUserNumber = "" Then End If Not IsNumeric(varUserNumber) Then GoTo Loopback If varUserNumber < 1 Or varUserNumber > 10 Then GoTo Loopback 'message to show if the value doesn't found. strMsg = "Your value, " & varUserNumber & _ ", was not found in the array." 'loop through the array and match each value with the _ the value you have entered in the input box. For i = 1 To UBound(myArray) If myArray(i) = varUserNumber Then strMsg = "Your value, " & varUserNumber & _ ", was found at position " & i & " in the array." Exit For End If Next i 'message box in the end MsgBox strMsg, vbOKOnly + vbInformation, "Linear Search Result" End Sub
- In the first part of the code, you have variables that you need to use in the code further.
- After that, the next part is to generate random numbers by using RND to get you 10 values for the array.
- Next, an input box to let enter the value that you want to search within the array.
- In this part, you have a code for the string to use in the message box if the value you have entered is not found.
- This part of the code uses a loop to loop through each item in the array and check if the value that you have entered is in the array or not.
- The last part of the code shows you a message about whether a value is found or not.