How does this calculation work?

[gnarlydude]

Hi,

I found this calculation on FileMaker's web site and it's the coolest thing since pork chops on a stick. It formats Social Security numbers with hyphens so you don't have to manually enter them. I understand most of it but would like to understand it all. Here it is:

left(SocSec, 3)&"-"&middle(SocSec,4,2)&"-"&right(SocSec,4)

Ok, I understand that the first part of this calculation takes the first 3 digits in a social security number and places them to the left of the first hyphen. The opposite happens in the last part of the calculation with the last 4 digits of the social security number. What I don't understand is what the number "4" in the [color:"blue"]middle(SocSec,4,2) does. The 2 obviously is the 2 digits surrounded by the hyphens. What's that 4 doing?

Also, does anyone have a suggestion on a good book/reference manual for FileMaker Pro? I am pretty good with the basics but calculations just boggle my mind. I would like a book that really examines how Filemaker calculations work (and what all the different functions do) from the perspective of a relative newbie.

Any suggestions?

Thanks,

Joe

[slstrother]

middle(SocSec,4,2)

The 4 designates the character to start on.

[SteveB]

A really good book that will immediately help you understand calculations and lots else is Scriptology by Matt Petrowsky and John Mark Osborne. Its a little out of date (covers thru version 4), but still really useful. They have loads of techniques and example files. www.scriptology.com

[RussBaker]

I use "Special Edition Using FileMaker Pro 5" in addition to Scriptology. Scriptology is great and goes deep into several areas, but also leave some other areas untouched. I recall that Amazon had a package deal on both these books a month or so ago - but the current version of Scriptology is meant to be getting a bit hard to get hold of now.

[gnarlydude]

Boy, they don't exactly give Scriptology away ($80.00 at amazon) do they? I already have Using File maker Pro Special Edition but haven't really had much time to dig into it.

Thanks,

Joe

[gnarlydude]

Thanks for the info slstorgher,

How come you don't have to tell the left and the right what charactor to start on? For instance:

left(SocSec,1,3)

or

right(SocSec,5,4)

Joe

[lscott]

left( means the left most characters ---- same with right( being the right most characters