What is an Array?
We know very well that a variable is a container to store a value. Sometimes, developers are in a position to hold more than one value in a single variable at a time. When a series of values is stored in a single variable, then it is known as an array variable.
Array Declaration
Arrays are declared the same way a variable has been declared except that the declaration of an array variable uses parenthesis. In the following example, the size of the array is mentioned in the brackets.
'Method 1 : Using Dim
Dim arr1() 'Without Size
'Method 2 : Mentioning the Size
Dim arr2(5) 'Declared with size of 5
'Method 3 : using 'Array' Parameter
Dim arr3
arr3 = Array("apple","Orange","Grapes")
- Although, the Array size is indicated as 5, it can hold 6 values as array index starts from ZERO.
- Array Index Cannot be Negative.
- VBScript Arrays can store any type of variable in an array. Hence, an array can store an integer, string or characters in a single array variable.
Assigning Values to an Array
The values are assigned to the array by specifying array index value against each one of the values to be assigned. It can be a string.
Example
<!DOCTYPE html>
<html>
<body>
<script language = "vbscript" type = "text/vbscript">
Dim arr(5)
arr(0) = "1" 'Number as String
arr(1) = "VBScript" 'String
arr(2) = 100 'Number
arr(3) = 2.45 'Decimal Number
arr(4) = #10/07/2013# 'Date
arr(5) = #12.45 PM# 'Time
document.write("Value stored in Array index 0 : " & arr(0) & "<br />")
document.write("Value stored in Array index 1 : " & arr(1) & "<br />")
document.write("Value stored in Array index 2 : " & arr(2) & "<br />")
document.write("Value stored in Array index 3 : " & arr(3) & "<br />")
document.write("Value stored in Array index 4 : " & arr(4) & "<br />")
document.write("Value stored in Array index 5 : " & arr(5) & "<br />")
</script>
</body>
</html>
When the above code is saved as .HTML and executed in Internet Explorer, it produces the following result −
Value stored in Array index 0 : 1 Value stored in Array index 1 : VBScript Value stored in Array index 2 : 100 Value stored in Array index 3 : 2.45 Value stored in Array index 4 : 7/10/2013 Value stored in Array index 5 : 12:45:00 PM
Multi Dimension Arrays
Arrays are not just limited to single dimension and can have a maximum of 60 dimensions. Two-dimension arrays are the most commonly used ones.
Example
In the following example, a multi-dimension array is declared with 3 rows and 4 columns.
<!DOCTYPE html>
<html>
<body>
<script language = "vbscript" type = "text/vbscript">
Dim arr(2,3) ' Which has 3 rows and 4 columns
arr(0,0) = "Apple"
arr(0,1) = "Orange"
arr(0,2) = "Grapes"
arr(0,3) = "pineapple"
arr(1,0) = "cucumber"
arr(1,1) = "beans"
arr(1,2) = "carrot"
arr(1,3) = "tomato"
arr(2,0) = "potato"
arr(2,1) = "sandwitch"
arr(2,2) = "coffee"
arr(2,3) = "nuts"
document.write("Value in Array index 0,1 : " & arr(0,1) & "<br />")
document.write("Value in Array index 2,2 : " & arr(2,2) & "<br />")
</script>
</body>
</html>
When the above code is saved as .HTML and executed in Internet Explorer, it produces the following result −
Value stored in Array index : 0 , 1 : Orange Value stored in Array index : 2 , 2 : coffee
Redim Statement
ReDim Statement is used to declare dynamic-array variables and allocate or reallocate storage space.
ReDim [Preserve] varname(subscripts) [, varname(subscripts)]
- Preserve − An Optional parameter used to preserve the data in an existing array when you change the size of the last dimension.
- varname − A Required parameter, which denotes Name of the variable, which should follow the standard variable naming conventions.
- subscripts − A Required parameter, which indicates the size of the array.
Example
In the below example, an array has been redefined and then preserved the values when the existing size of the array is changed.
Note − Upon resizing an array smaller than it was originally, the data in the eliminated elements will be lost.
<!DOCTYPE html>
<html>
<body>
<script language = "vbscript" type = "text/vbscript">
Dim a()
i = 0
redim a(5)
a(0) = "XYZ"
a(1) = 41.25
a(2) = 22
REDIM PRESERVE a(7)
For i = 3 to 7
a(i) = i
Next
'to Fetch the output
For i = 0 to ubound(a)
Msgbox a(i)
Next
</script>
</body>
</html>
When we save the above script as HTML and execute it in Internet Explorer, it produces the following result.
XYZ 41.25 22 3 4 5 6 7
Array Methods
There are various inbuilt functions within VBScript which help the developers to handle arrays effectively. All the methods that are used in conjunction with arrays are listed below. Please click on the method name to know in detail.
| Function | Description |
|---|---|
| LBound | A Function, which returns an integer that corresponds to the smallest subscript of the given arrays. |
| UBound | A Function, which returns an integer that corresponds to the Largest subscript of the given arrays. |
| Split | A Function, which returns an array that contains a specified number of values. Splitted based on a Delimiter. |
| Join | A Function, which returns a String that contains a specified number of substrings in an array. This is an exact opposite function of Split Method. |
| Filter | A Function, which returns a zero based array that contains a subset of a string array based on a specific filter criteria. |
| IsArray | A Function, which returns a boolean value that indicates whether or not the input variable is an array. |
| Erase | A Function, which recovers the allocated memory for the array variables. |
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