strings

Easy String Searches with the VBScript Instr function

I recently had a situation where I needed to find string inside a string to parse the larger string into usable and separate chunks of data. In writing this script, I realized I’ve not shared this gem of a function with you previously… and it really makes matters easier when you are manipulating strings.

That function is the Instr function. When configured with the proper parameters, by default, it will return the FIRST location in a string where a sub-string occurs. (Hint: this is where a mid() function would come in handy after you have that starting location). If the sub-string is not found, the function returns 0. The syntax is as follows:

Instr(StartPostion, StringToSearch,StringtoFind, Compare)

 The script I wrote really is a blog entry of it’s own, and will be, but I wanted to first introduce you to this great function and let you have a chance to play with it and see some code in action. Below is an example script that takes a string and searched for specific sub strings, then returns the location in the string where the sub string occurs.

Option explicit
Dim StrSource

StrSource = “Now I can find a word In a long string of words in a sentance.”

WScript.Echo(InStr(1,StrSource,”In”))
WScript.Echo(InStr(1,StrSource,”in”))
WScript.Echo(InStr(1,StrSource,” in “))
WScript.Echo(InStr(1,StrSource,”now”))

Below is the output from the script. Notice, the following:

• The case of in and In in the sub-string being searched for and the positions it returns?
• Notice the substring “in ” returns something entirely different?
• Notice the substring now returns 0?

23
12
48
0

Enjoy!

Using special characters in VBScript strings

I just realized I’ve been using Visual Basic String constants in my scripts with little to no explanation. We’ll rectify that situation right now!

When dealing with strings in VBScript, you occasionally need to add formatting characters to a string, so that when it is displayed on the screen or in a file it looks correct. If you know your ASCII chart you can certainly preform this with a “& chr(X) &”.However, if you don’t know what ASCII value a tab is (it’s 9) then you can simply use Visual Basic’s string constants in your scripts and have the added benefit if making it easier to read!

The constants and their meanings are listed below: