For a value type, you use an initializer to supply an expression to be assigned to the variable. The expression must evaluate to a constant that can be calculated at compile time. If an initializer is specified and a data type is not specified in an As clause, type inference is used to infer the data type from the initializer.
In the following example, both num1 and num2 are strongly typed as integers. In the second declaration, type inference infers the type from the value 3. Type inference applies at the procedure level.
It does not apply outside a procedure in a class, structure, module, or interface. For information about what happens when a data type or initializer is not specified, see Default Data Types and Values later in this topic.
You can use an object initializer to declare instances of named and anonymous types. The following code creates an instance of a Student class and uses an object initializer to initialize properties. You can declare several variables in one declaration statement, specifying the variable name for each one, and following each array name with parentheses.
Multiple variables are separated by commas. If you declare more than one variable with one As clause, you cannot supply an initializer for that group of variables. You can specify different data types for different variables by using a separate As clause for each variable you declare. Each variable takes the data type specified in the first As clause encountered after its variablename part. You can declare a variable to hold an array , which can hold multiple values.
To specify that a variable holds an array, follow its variablename immediately with parentheses. For more information about arrays, see Arrays. You can specify the lower and upper bound of each dimension of an array. To do this, include a boundslist inside the parentheses. For each dimension, the boundslist specifies the upper bound and optionally the lower bound. The lower bound is always zero, whether you specify it or not. Each index can vary from zero through its upper bound value.
The following two statements are equivalent. Each statement declares an array of 21 Integer elements. When you access the array, the index can vary from 0 through The following statement declares a two-dimensional array of type Double. Note that an upper bound represents the highest possible value for the index, not the length of the dimension. The length of the dimension is the upper bound plus one. You can leave all the bounds blank in an array declaration.
If you do this, the array has the number of dimensions you specify, but it is uninitialized. Dim statements allow you to stay in control of what is being declared. If the variables are not declared then the Visual Basic Editor decides what data type the variable will be in order for the code not to fail. Declaring your variables is considered best practice.
It is an ordered catalogue of the short cuts you will use in code with the added advantage of your code running faster with correct use of Dim statements. In short no - but The Dim statement should always be used in conjunction with the Option Explicit statement.
The Option Explicit term forces the declaration of all variables and I heartily recommend getting into the habit of using it. You can force all workbooks to have Option Explicit at the top of each sheet and regular module by going through the following process. Under Editor - Require Variable Declaration needs to be ticked.
The VBA language is reasonably easy to learn for people using Excel a lot but the terms first need to be understood. The Dim statement is a great place to start, after you have pushed your recorded macros to the limit.
There are a bunch of reasons why you should use Dim and declare your variables. Here are the ones I can think of please leave a comment if you can think of any other reasons and I will add them to the list :. Hopefully this provides you with the basic concepts of why you see all those Dims floating around out on the internet. It took me quite some time before I realized the importance of declaring my variables. However, after I made an effort to really understand the concept, it really helped me write my VBA code in less time and with fewer errors.
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Thank you so much for reading and I hope I can continue to provide you with great content in the future! Check out all the free tutorials and VBA code snippets! Theraot Theraot I've heard "declare in memory" also. Also I am now going to insist to people that this is what Dim actually stands for — Jacob Stamm.
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