Thanks for the update Michael but when bringing old posts back to live you should consider changes of AppleScript through the years as well. Improvements over Michaels scripts are:

- Since AppleScript 2.0 the script should use (character) id instead of ASCII character command.
- AppleScript 2.0 is Unicode, by default all Unicode spaces are supported now, not only limited to MacRoman whitespaces
- BugFix: The handler will return "" if the string contains only whitespaces
- BugFix: The handler will return "" if the string is empty
- Optimization: The string will only be trimmed once, not twice (text n thru n ...)
- Use justification constants left and right to indicate direction, missing value (any value) a full trim will be applied.
- pstrCharToTrim works now with a more obvious value than a boolean. Use missing value (read: undefined) to use default whitespaces. It will also use default values when the given object is not a list instead of returning an error.

Applescript:

set strTest to "    Hello World! "
trimThis(strTest, missing value, left) -- result: "Hello World! "
trimThis(strTest, missing value, right) -- result: "    Hello World!"
trimThis(strTest, {tab, return, linefeed}, missing value) -- result: "Hello World! "

on trimThis(pstrSourceText, pstrCharToTrim, pstrTrimDirection)
   -- pstrCharToTrim     : A list of characters to trim, or true to use default
   -- pstrSourceText : The text to be trimmed
   -- pstrTrimDirection : Direction of Trim left, right or any value for full
   
   set strTrimedText to pstrSourceText
   
   -- If undefinied use default whitespaces
   if pstrCharToTrim is missing value or class of pstrCharToTrim is not list then
       -- trim tab, newline, return and all the unicode characters from the 'separator space' category
       -- [url]http://www.fileformat.info/info/unicode/category/Zs/list.htm[/url]
       set pstrCharToTrim to {tab, linefeed, return, space, character id 160, character id 5760, character id 8192, character id 8193, character id 8194, character id 8195, character id 8196, character id 8197, character id 8198, character id 8199, character id 8200, character id 8201, character id 8202, character id 8239, character id 8287, character id 12288}
   end if
   
   set lLoc to 1
   set rLoc to count of strTrimedText
   
   --- From left to right, get location of first non-whitespace character
   if pstrTrimDirection is not right then
       repeat until lLoc = (rLoc + 1) or character lLoc of strTrimedText is not in pstrCharToTrim
           set lLoc to lLoc + 1
       end repeat
   end if
   
   -- From right to left, get location of first non-whitespace character
   if pstrTrimDirection is not left then
       repeat until rLoc = 0 or character rLoc of strTrimedText is not in pstrCharToTrim
           set rLoc to rLoc - 1
       end repeat
   end if
   
   if lLoc ≥ rLoc then
       return ""
   else
       return text lLoc thru rLoc of strTrimedText
   end if
end trimThis

Last edited by DJ Bazzie Wazzie (2015-08-10 04:44:23 am)

@DJ:  Thanks for the backhanded compliment. 

When providing what you think is an improved version of someone else's script, it is not necessary to be critical if nothing wrong was done.  Whether or not your version is better will be left up to the reader.

I see nothing wrong with using the ASCII character command.  It works and is more obvious than the character ID approach.
I also think it is more obvious to use a value of "full" rather than missing value for parameter pstrTrimDirection.  There's no reason not to allow for both.

Your "optimization" of trimming once instead of twice is a very minor optimization.  But it good.

Thanks for sharing your version.  It is good the thread is alive again. 

OK, I did not realize the ASCII commands had been depreciated.

From the Apple Guidelines:

Maybe even better is to use the constants:

You're beating a dead horse. 

I noted it was depreciated, and even quoted the Apple Guidelines.
I was already in agreement to not use the ASCII commands.

Hi peavine.

theRange is set to the range of the last character in the string which isn't in the set of characters to be trimmed. The code's then meant to return the text from the beginning of the string up to and including that character. But in fact substringToIndex: "Returns a new string containing the characters of the receiver up to, but not including, the one at a given index." So to include that last character, the given index has to be the character's location plus its length:

Applescript:

set anNSString to anNSString's substringToIndex:((theRange's location) + (theRange's |length|))

Shane's script includes the ability to remove characters from the beginning, the end, or both the beginning and end of a string. I seldom need to do all of these in one script and, for economy of code, decided to divide Shane's script into three handlers, which I've included below. I've also included a fourth handler which works on a string with multiple paragraphs.

The operation of these scripts requires no explanation, except to note that the handlers' second parameter can either be specific characters or missing value, and, in the latter case, the character set whitespaceAndNewlineCharacterSet is used. So, when calling one of the handlers, all of the following are valid:

trimLeadingCharacters(theString, "-" & " ")
trimTrailingCharacters(theString, space & tab)
trimLeadingAndTrailingCharacters(theString, missing value)

I ran some timing tests with these handlers with single-paragraph strings and they generally took about 3 milliseconds to run--this assumes that the foundation framework is already in memory. I tested the fourth handler with a string that contained 301 paragraphs, and the timing result was 265 milliseconds.

TRIM LEADING CHARACTERS

Applescript:

on trimLeadingCharacters(theString, theCharacters)
   if theCharacters = missing value then
       set theCharacters to current application's NSCharacterSet's whitespaceAndNewlineCharacterSet()
   else
       set theCharacters to current application's NSCharacterSet's characterSetWithCharactersInString:theCharacters
   end if
   
   set theString to current application's NSString's stringWithString:theString
   set theRange to theString's rangeOfCharacterFromSet:(theCharacters's invertedSet())
   if |length| of theRange = 0 then return ""
   return (theString's substringFromIndex:(theRange's location)) as text
end trimLeadingCharacters

TRIM TRAILING CHARACTERS

Applescript:

on trimTrailingCharacters(theString, theCharacters)
   if theCharacters = missing value then
       set theCharacters to current application's NSCharacterSet's whitespaceAndNewlineCharacterSet()
   else
       set theCharacters to current application's NSCharacterSet's characterSetWithCharactersInString:theCharacters
   end if
   
   set theString to current application's NSString's stringWithString:theString
   set theRange to theString's rangeOfCharacterFromSet:(theCharacters's invertedSet()) options:(current application's NSBackwardsSearch)
   if |length| of theRange = 0 then return ""
   return (theString's substringToIndex:((theRange's location) + (theRange's |length|))) as text
end trimTrailingCharacters

TRIM LEADING AND TRAILING CHARACTERS

Applescript:

on trimLeadingAndTrailingCharacters(theString, theCharacters)
   if theCharacters = missing value then
       set theCharacters to current application's NSCharacterSet's whitespaceAndNewlineCharacterSet()
   else
       set theCharacters to current application's NSCharacterSet's characterSetWithCharactersInString:theCharacters
   end if

   set theString to current application's NSString's stringWithString:theString
   set theString to theString's stringByTrimmingCharactersInSet:theCharacters
   return theString as text
end trimLeadingAndTrailingCharacters

TRIM LEADING AND TRAILING CHARACTERS - STRING HAS MULTIPLE PARAGRAPHS

Applescript:

on trimLeadingAndTrailingCharacters(theString, theCharacters)
   if theCharacters = missing value then
       set theCharacters to current application's NSCharacterSet's whitespaceCharacterSet()
   else
       set theCharacters to current application's NSCharacterSet's characterSetWithCharactersInString:theCharacters
   end if
   
   set theStrings to (current application's NSString's stringWithString:theString)'s componentsSeparatedByString:linefeed
   set cleanedStrings to current application's NSMutableArray's new()
   repeat with aString in theStrings
       set aString to (aString's stringByTrimmingCharactersInSet:theCharacters)
       (cleanedStrings's addObject:aString)
   end repeat
   return (cleanedStrings's componentsJoinedByString:linefeed) as text
end trimLeadingAndTrailingCharacters

Last edited by peavine (2021-09-04 07:12:37 am)

KniazidisR. Thanks for looking at my scripts and for your suggestion.

Our scripts appear to perform somewhat different tasks. My script removes the specified characters (whitespace as currently written) from the beginning and end of every paragraph in the text. Thus, in my timing tests, the script trims 3001 paragraphs. Your script removes the specified characters from the beginning and end of the entire text rather than the individual paragraphs. If that is correct, it doesn't appear the timing-test results of our scripts should be compared. Am I confused as to what your script does?

Last edited by peavine (2021-09-08 06:36:21 am)

Anyone reading this thread may have need of a script that trims text in a file or on the clipboard, and I've included below scripts that perform these tasks. Their operation requires no real explanation, except to note that the file-trimming script creates a new file, which has the same name as the original but with the word "trimmed" appended. Also, the scripts trim both leading and trailing characters, although this can be changed by disabling the applicable repeat loop.

This script trims text in a file:

Applescript:

-- Revised 2021.10.05

use framework "Foundation"
use scripting additions

on main()
   set theCharacters to space & tab -- add characters if desired but precede with ampersand
   set characterEncoding to current application's NSUTF8StringEncoding
   
   set theFile to POSIX path of (choose file)
   set theTrimmedFile to getFileName(theFile)
   
   set theText to ((current application's NSString's stringWithContentsOfFile:theFile encoding:characterEncoding |error|:(missing value)) as text)
   if theText = "missing value" then display alert "An error has occurred" message "The selected file may not be a text file" buttons {"OK"} cancel button 1 as critical
   set theText to trimText(theText, theCharacters)
   (current application's NSString's stringWithString:theText)'s writeToFile:theTrimmedFile atomically:true encoding:characterEncoding |error|:(missing value)
end main

on trimText(theText, theCharacters)
   script o
       property untrimmedParagraphs : (paragraphs of theText)
       property trimmedParagraphs : {}
   end script
   
   repeat with aParagraph in o's untrimmedParagraphs
       set aParagraph to contents of aParagraph
       try
           repeat while text 1 of aParagraph is in theCharacters -- remove leading characters
               set aParagraph to text 2 thru -1 of aParagraph
           end repeat
           repeat while text -1 of aParagraph is in theCharacters -- remove trailing characters
               set aParagraph to text 1 thru -2 of aParagraph
           end repeat
       on error
           set aParagraph to ""
       end try
       set the end of o's trimmedParagraphs to aParagraph
   end repeat
   
   set text item delimiters to {linefeed}
   set o's trimmedParagraphs to (o's trimmedParagraphs as text)
   set text item delimiters to {""}
   return o's trimmedParagraphs
end trimText

on getFileName(theFile)
   set theFile to current application's NSString's stringWithString:theFile
   set fileBase to theFile's stringByDeletingPathExtension()
   set fileExtension to theFile's pathExtension()
   return ((fileBase's stringByAppendingString:" (trimmed)")'s stringByAppendingPathExtension:fileExtension)
end getFileName

main()

This script trims the content of the clipboard:

Applescript:

-- Revised 2021.10.05

on main()
   set theCharacters to space & tab -- add characters if desired but precede with ampersand
   try
       set theText to the clipboard as text
   on error
       display alert "An error has ocurred" message "Text was not found on the clipboard" as critical
       error number -128
   end try
   set the clipboard to trimText(theText, theCharacters)
end main

on trimText(theText, theCharacters)
   script o
       property untrimmedParagraphs : (paragraphs of theText)
       property trimmedParagraphs : {}
   end script
   
   repeat with aParagraph in o's untrimmedParagraphs
       set aParagraph to contents of aParagraph
       try
           repeat while text 1 of aParagraph is in theCharacters -- remove leading characters
               set aParagraph to text 2 thru -1 of aParagraph
           end repeat
           repeat while text -1 of aParagraph is in theCharacters -- remove trailing characters
               set aParagraph to text 1 thru -2 of aParagraph
           end repeat
       on error
           set aParagraph to ""
       end try
       set the end of o's trimmedParagraphs to aParagraph
   end repeat
   
   set text item delimiters to {linefeed}
   set o's trimmedParagraphs to (o's trimmedParagraphs as text)
   set text item delimiters to {""}
   return o's trimmedParagraphs
end trimText

main()

Last edited by peavine (2021-10-05 07:20:54 am)