Array and functions

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.

CREATING ARRAYS
• We can create arrays several ways, depending on whether they are
static or dynamic.
• Static arrays - Static arrays stay a fixed size throughout their lifetime—
that is, the index size remains constant. Thus, when we create a static
array, we must know how many items the array will contain
throughout its lifetime.
• Dynamic arrays – Suppose if we don't know the number of items or
don’t know that the array's index size will change, we need to create a
dynamic array. Dynamic arrays don't have a fixed index size. We can
increase or decrease the index size at any time.

Array Declaration and Assigning Values to an Array
Example 1:
option explicit
dim arr(3)
arr(0)=1
arr(1)="2"
arr(2)="sun"
arr(3) = #10/07/2013#
msgbox arr(0)
msgbox arr(1)
msgbox arr(2)
msgbox arr(3)

Example 2:
option explicit
Dim arr
arr=array("5",100,45,464)
msgbox arr(0)
msgbox arr(1)
msgbox arr(2)
msgbox arr(3)

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:
Option explicit
Dim arr(1,2) //2 rows and 3 columns
arr(0,0) = "A"
arr(0,1) = "B"
arr(0,2) = "C"
arr(1,0) = "Dr"
arr(1,1) = "E"
arr(1,2) = "F"
msgbox arr(0,0)
msgbox arr(0,1)
msgbox arr(0,2)
msgbox arr(1,0)
msgbox arr(1,1)
msgbox arr(1,2)

ReDim Statement
• ReDim Statement is used to declare dynamic-array variables and allocate or reallocate storage space.
Example:
option explicit
dim arr()
redim arr(5)
arr(0)=1
arr(1)=2
arr(2)=3
arr(3)=4
arr(4)=5
redim preserve arr(10)
arr(6)=7
msgbox arr(0)
msgbox arr(1)
msgbox arr(6)
redim preserve arr(4)
msgbox arr(0)
msgbox arr(1)
msgbox arr(2)
msgbox arr(3)
msgbox arr(4)

Array Methods
LBound Function
• The LBound Function returns the smallest subscript of the specified array.
Hence, LBound of an array is ZERO.
Example:
option explicit
dim arr(5)
arr(0)=1
arr(1)=2
arr(2)=3
arr(3)=4
arr(4)=5
msgbox lbound(arr)

UBound Function
The UBound Function returns the Largest subscript of the specified
array. Hence, this value corresponds to the size of the array.
Example:
option explicit
dim arr(5)
arr(0)=1
arr(1)=2
arr(2)=3
arr(3)=4
arr(4)=5
msgbox ubound(arr)

Split Function
• A Split Function returns an array that contains a specific number of values
split based on a Delimiter.
Example:
option explicit
dim arr,b,c,i
arr=split("sun & technology & integrators","&")
b=ubound(arr)
for i=0 to b
msgbox arr(i)
next

Join Function
• 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.
Example:
option explicit
dim arr,b,c
arr=array("sun","technology","integrators")
b=join(arr)
msgbox b
c=join(arr,0)
msgbox c

Filter Function
A Filter Function, which returns a zero-based array that contains a subset of a
string array based on a specific filter criteria.
Example:
option explicit
Dim MyIndex
Dim MyArray (3)
MyArray(0) = "Sunday"
MyArray(1) = "Monday"
MyArray(2) = "Tuesday"
MyIndex = Filter(MyArray, "Mon")
msgbox myindex(0)

IsArray Function
The IsArray Function returns a Boolean value that indicates whether or NOT the
specified input variable is an array variable.
Example:
option explicit
dim a,b
a=array("Red","Blue","Yellow")
b = "12345"
msgbox isarray(a)
msgbox isarray(b)

Erase Function
The Erase Function is used to reset the values of fixed size arrays and free the memory of the
dynamic arrays.
Example:
option explicit
dim a(2)
a(0)="hello"
a(1)=22
a(2)=08
msgbox a(0)
msgbox a(1)
msgbox a(2)
erase a
msgbox a(0)
msgbox a(1)
msgbox a(2)

What is a Function?
A function is a group of reusable code which can be called anywhere in your
program. This eliminates the need of writing same code over and over again.
This will enable programmers to divide a big program into a number of small and
manageable functions.
• Function Definition
Before we use a function, we need to define that particular function. The most
common way to define a function in VBScript is by using the Function keyword,
followed by a unique function name and it may or may not carry a list of
parameters and a statement with an End Function keyword

Example 1:
option explicit
Function Hello()
msgbox("Hello")
End Function
call hello()

Example2:
option explicit
Function Hello(name,age)
msgbox( name & " is " & age & " years old.")
End Function
call hello("vb",4)

Example3:
option explicit
Function sum(number1,number2)
sum = number1 + number2
End Function
Dim total
total = sum(100,9)
msgbox total

Sub-Procedures
Sub-Procedures are similar to functions but there are few differences.
• Sub-procedures DONOT Return a value while functions may or may not return
a value.
• Sub-procedures Can be called without call keyword.
• Sub-procedures are always enclosed within Sub and End Sub statements.

Example:
option explicit
sub Hello()
msgbox("Hello")
End sub
hello()

VBScript ByVal Parameters:
If ByVal is specified, then the arguments are sent as byvalue when the function or
procedure is called.
Example:
option explicit
Function fnadd(Byval num1, Byval num2)
num1 = 4
num2 = 5
End Function
Dim x,y,res
x=6
y=4
res= fnadd(x,y)
msgbox x
msgbox y

VBScript ByRef Parameters
If ByRef is specified, then the arguments are sent as a reference when the function or
procedure is called.
Example:
option explicit
Function fnadd(byRef num1,ByRef num2)
num1 = 4
num2 = 5
End Function
Dim x,y,res
x=6
y=4
res= fnadd(x,y)
msgbox x
msgbox y

Array and functions

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Array and functions