Understanding operators and built-in String functions in VBScript

In the previous article we discuss on defining a variable, different types of variables in VBscript . In this article we will discuss on various operators and built in string functions in VBScript as are frequently used in QTP.

Let us start by discussing different types of operators. Operators are broadly classified into 
- Logical Operators
- Arithmetic operators
- Comparison Operators

Logical Operators - Logical Operator are used to perform logical operations and returns boolean value as true or false based on the inputs provided and operator used.

Logical Operator used are Not ( Not True = false)
And (Returns true if both A and B are true, false otherwise)
OR(Returns true if either of A or B is true)
xor ( returns false if either of A or B is true)

Arithmetic Operators - We have been performing arithmetic operation from the day we start our education. So this is easy.  The various arithmetic operators in VBScript  are +(addition), - (subtraction), *(multiply), /(division), 
\(integer division, return the quotient), 
mod (a mod b, gives the remainder on dividing a by b),
^(exponential function).
Of the Operators , defined above , + is used to concatenate two strings also.

Comparison Operators are used to compare two variable . Example of comparison Operators are =(equality), <>(Inequality), <(Less than ), <(greater than), <=,>= ( greater than or equal to). To Compare strings, we can use strcomp function.

We have discussed the various operators used in VBScript.Now let us discuss on various string functions that are inbuilt in vbscript and are useful to work with strings

Instr function - This function returns the location of first occurrence of one string within another string. 
str1 = "This is testing blog on VBScript testing"
str2 = "testing"
iLoc = Instr(1,str1,str2,0)
msgbox iLoc

Syntax is InStr([start,]string1,string2[,compare]). start and compare are optional parameters with default value as 1 and 0(binary compare)

Instrrev function - This function returns the location of first occurrence of one string within another string. While Instr starts search from start of string,In Instrrev The search begins from the end of string. But the location returned is from start of string.
str1 = "This is testing blog on VBSCRIPT testing test"
str2 = "testing"
iLoc = Instrrev(str1,str2,-1,0)
msgbox iLoc

Syntax is InStrRev(string1,string2,[start,][compare]). start and compare are optional parameters with default value as -1(end of string) and 0(binary compare)

LCase(string) converts string to lowercase
Ucase(string) converts to uppercase.

len(string) returns number of character in a string.

Left, right and mid are used to return specified characters from the string starting from left,right, and middle of string
str3 = left(str1,10)
str4= right(str1, 10)
str5 = mid(str1,5,10) 

LTrim,RTrim and trim are used to remove spaces on the left, right or middle of a string
str6 = trim(str1)

strComp compares two string and returns value as 0 if both string matches.
blncomp = strcomp(str1,str2[,compare])

space(number) returns the space character returned times as provided in the argument.

String(number, character) returns a string with character repeated number of times as provided in the arguments.