Applescript convert variable into a string with commas for CSV

Question

I have a variable that contains {"THIS", "THAT"} that I am trying to write to a csv so that the csv formats as THIS,THAT. Current it just spits out as THISTHAT.

I think I need to repeat though the variable but I am not sure...

the code is as follows (check the ---> for the important bits):

tell application "Adobe InDesign CC 2014"   
delete unused swatches of document 1
set _NotUSED to {"None", "Paper", "Black", "Registration", "Keyline", "ImageLabel", "C=0 M=0 Y=0 K=37", "C=0 M=100 Y=100 K=0", "Map this to white ->", "Dieline", "C=0 M=100 Y=0 K=0"} as string

try
---> Get the variables
    set _UpDatedList to get (name of swatches of document 1 whose name is not in _NotUSED)

on error

    display alert {"Your document has no spot colours"}

end try

end tell

set filePath to (path to desktop as text) & "Pantones.csv"

---> Set the theString to the variables
set theString to _UpDatedList as string

set theResult to writeTo(filePath, theString, text, false)

if not theResult then display dialog "There was an error writing the data!"

on writeTo(targetFile, theData)
try

    set openFile to open for access file targetFile with write permission

---> write the variables to csv
    write theData to openFile
    close access openFile
    return true
    on error
    try
        close access file targetFile
    end try
    return false
end try
end writeTo

Answer 1

Try this, the easiest way to convert a list to CSV is to use text item delimiters.
The main problem is the coercion to string in the 3rd line. Delete as string.

tell application "Adobe InDesign CC 2014"
    delete unused swatches of document 1
    set _NotUSED to {"None", "Paper", "Black", "Registration", "Keyline", "ImageLabel", "C=0 M=0 Y=0 K=37", "C=0 M=100 Y=100 K=0", "Map this to white ->", "Dieline", "C=0 M=100 Y=0 K=0"}
    try
        set _UpDatedList to (get name of swatches of document 1 whose name is not in _NotUSED)
    on error
        display alert "Your document has no spot colours" buttons {"Cancel"}
        return -- abort the script
    end try
end tell

set filePath to (path to desktop as text) & "Pantones.csv"

set {TID, text item delimiters} to {text item delimiters, ","}
set csvString to _UpDatedList as text
set text item delimiters to TID

set theResult to writeTo(filePath, csvString)

if not theResult then display dialog "There was an error writing the data!"

on writeTo(targetFile, theData)
    try
        set openFile to open for access file targetFile with write permission
        write theData to openFile
        close access openFile
        return true
    on error
        try
            close access file targetFile
        end try
        return false
    end try
end writeTo