Automate renaming of files from lists

Question

I have been looking for a utility that cna do this for me, but can't find one.
So I have decided to try and do this via Applescript. But this is getting a bit too complicated for me.
I have about 35,000 files which have to be renamed.
The current file name structure is : AABBBBBBB_CDDD.EEE
"AA_" has to be deleted - *so far so good!*.
The 7 letter code "BBBBBBB" has to be replaced with a new 5 digit product code, but ther rest of the file name ("C_DDD.EEE") must remain the same.
I have an Excell file with the old product code in the first column, and the new product code in the second column.
Anybody out there who can help me?
Many thanks, cos I'm getting seriously bogged down!

Answer 1

*First try this in Script Editor and then try the 'Finder' version [between the (* *) ]*
set changeMidstringInto to text returned of (display dialog "Set BBBBBBB to following 5 digit code..." default answer "")
set theFileName to "AABBBBBBB_CDDD.EEE" -- -REPLACE WITH name of (info for curItem)
set ASTID to AppleScript's text item delimiters
set AppleScript's text item delimiters to "_"
set myStartString to text item 1 of theFileName
set myStartString to ""
set myMidString to text item -3 of theFileName
set myMidString to changeMidstringInto as string
set myEndString to text items -2 thru -1 of theFileName as string
set theNewFileName to myMidString & myEndString
set theFileName to theNewFileName as string
set AppleScript's text item delimiters to ""
set AppleScript's text item delimiters to ASTID
return theFileName
set changeMidstringInto to text returned of (display dialog "Set BBBBBBB to following 5 digit code..." default answer "")
tell application "Finder"
activate
set frontmost of application "Finder" to true
-- [Optional] select Finder window 1
set curItems to selection -- OR || set curItems to every item in window 1
repeat with curItem in curItems
set theFileName to name of (info for curItem)
set ASTID to AppleScript's text item delimiters
set AppleScript's text item delimiters to "_"
set myStartString to text item 1 of theFileName
set myStartString to ""
set myMidString to text item -3 of theFileName
set myMidString to changeMidstringInto as string
set myEndString to text items -2 thru -1 of theFileName as string
set theNewFileName to myMidString & myEndString
set theFileName to theNewFileName as string
set AppleScript's text item delimiters to ""
set AppleScript's text item delimiters to ASTID
--return theFileName
end repeat
end tell
*)