Simple question about the "Instr" functions

[w11184]

Hi everyone,

Sorry if this is a bit of a simple question but I just want to understand exactly how the "Instr" function works.

So in my scenario I want to extra the first letter of someone's surname and I actually manage to get it to work using the code below.

initial2: Mid([FullName],InStr([FullName]," ")+1,1)

However, what I want to know is why it produces an error if "+1" is omitted?

Thanks again. (Apologies, I know this is a basic one)

 

[plog]

give me a second, editing my post

 

[pr2-eugin]

What is the Error it produces? Invalid procedure Call? InStr returns the position of the String you are looking for in your case the Space character.

? Mid("HelloWorld", InStr("HelloWorld"," "), 1)

If the Function cannot find the String, it would return a value 0.

So the Mid function will have a value.

? Mid("HelloWorld",0,1)

So the Value ZERO is invalid for (most of the) String functions. Adding 1 makes it a valid argument, as 0+1 would make it 1.

Hope that helps !

 

[plog]

The issue isn't InStr, its that you are using [FullName] values without spaces in them. For those values InStr is returning 0 (http://www.techonthenet.com/access/functions/string/instr.php) which isn't a valid position for Mid (http://www.techonthenet.com/access/functions/string/mid.php) to begin at. Adding 1 to that is however and Mid works.

 

[w11184]

Thank you very much everyone it has just gotten a lot clearer. The "error" that I get is: #Func!

So I guess that by not putting in +1, it is asking it to return the space which isn't a string.