You can use the Array function with Dim to simultaneously create and fill dynamic arrays. Using ReDim is more direct and saves you from adding an extra line of code. You typically use ReDim when you already know a useful initial size for the dynamic array. For example, the codeĬreates a dynamic array whose initial size is 3. You can use ReDim without Dim to create a dynamic array that has an initial index size. For example, if you want to set an upper bound of 2 for arrUsers, you specify ReDim arrUsers(2)Īlthough you set arrUsers' index size, the array is empty. To set the array's size, you use a ReDim statement to set the upper bound. However, this array is uninitialized, which means you won't be able to use it until you set its size. For example, to create the dynamic array arrUsers, you can use the statement One way to create a dynamic array is to use a Dim statement in which you don't specify the array's upper bound. You can create a dynamic array in three ways: Once you set a static array's upper bound, you can't change it because the static array's index size remains constant. When you create a static array, the lower and the upper bound are 0 by default and the array is empty. The lower bound of static (and dynamic) VBScript arrays is always 0 because arrays always start with the 0 index. In other words, 2 is the array's upper bound. The value of 2 denotes that the array's indexes range from 0 to 2, which means the array can contain up to three items. The number in parentheses specifies the maximum value of indexes in the array. To create a static array, you use a Dim statement with the array's common name, such as Dim arrGroc(2) You can create arrays several ways, depending on whether they are static or dynamic. You can increase or decrease the index size at any time. Dynamic arrays don't have a fixed index size. If you don't know this information or you know that the array's index size will change, you need to create a dynamic array. Thus, when you create a static array, you must know how many items the array will contain throughout its lifetime. Static arrays stay a fixed size throughout their lifetime-that is, the index size remains constant. You can create two types of arrays: static and dynamic. The 0 index represents the first position, the 1 index represents the second position, and the 2 index represents the third position in the array. For example, if an array has three items, the indexes are 0, 1, and 2. The indexes always increment sequentially, starting from 0. The index number is an integer subscript that denotes an item's relative location in the list. The common name typically includes the prefix arr to denote that the variable contains data of the subtype Array. The common name is the name of the array variable. You reference each item in this list with a common name and index number. Think of an array as a list (e.g., a list of usernames).
An array lets you address many data values through the same variable. Unlike all the other subtypes I showed you last month, an array can hold more than one value. Related: Understanding VBScript: Operators I also cover multidimensional and nested arrays. This month, I take a close look at what Array variables, or simply arrays, are and how you can create, fill, resize, traverse, erase, split, and join them. However, I intentionally didn't discuss an important subtype: Array. Last month, I discussed three basic syntax elements: variables, constants, and subtypes.
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