How would I write a calculation to replace all non-alphanumeric characters with an underscore?

 

For example

 

ABC 123 (hello.world!)

 

would become

 

ABC_123__hello_world__

Like this?

Substitute (
	Text ; 
	[ " " ; "_" ] ; 
	[ "(" ; "_" ] ; 
	[ "." ; "_" ] ; 
	[ "!" ; "_" ] ; 
	[ ")" ; "_" ]
)             

There are probably better approaches but two options are 1. Build a recursive function to run each character through alphanumeric filter and if empty replace with _ or 2. a long substitution string substituting each possible character with _. I'm not in front of a computer at the moment to right a cf example but look into recursive custom functions. That's the direction I would go.

How would I write a calculation to replace all non-alphanumeric characters with an underscore?

 

I think we need a better definition of what is a "non-alphanumeric character" - or possibly, what is an "alphanumeric character". I suspect there may be an awful lot of characters in both categories - too many to consider each one individually. Perhaps it woud be best if you explained what type of input is expected here and - even ore importantly - what is the purpose of this exercise.

Recursive function is the answer. Here's what I came up with:

 

ReplaceOtherChars ( string ; ignorechars ; replacechars )

 

 

If ( Filter ( Left ( string ; 1 ) ; ignorechars ) = "" ; replacechar ; Left ( string ; 1 ) )

&

If ( Length ( string ) > 1 ;

ReplaceOtherChars ( Right ( string ; Length ( string ) - 1 ) ; ignorechars ; replacechar )

; "" )

 

Example: 

ReplaceOtherChars ( "ABC 123 (hello.world!)" ; "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" ; "_" )

Output: ABC_123__hello_world__

The reason I needed this is because native AppleScript no longer works for changing printers in Mac OS X v 10.9 Mavericks because "Printer Setup Utility" is no longer included, so I've realized that rather than installing an old version of Printer Setup Utility, I can just use the lpoptions terminal command to change printers, but the printer name seems to require all non-alphanumeric characters replaced with underscores, otherwise the command fails. (I still want users to be able to enter & view their printer names normally so this custom function will be used each time the printer is changed)