Speaking of Filter and Match...

[Roger Guay]

Hi Dick

Thank you so much for your time in sending me this solution. I’ve already learned a lot and I have yet to actually play with it!

Cheers,
Roger

> On Mar 14, 2022, at 5:08 PM, Dick Kriesel via use-livecode <use-livecode at lists.runrev.com> wrote:
> 
> 
> 
>> On Mar 13, 2022, at 1:05 PM, J. Landman Gay via use-livecode <use-livecode at lists.runrev.com> wrote:
>> 
>> On 3/12/22 8:54 PM, Roger Guay via use-livecode wrote:
>>> I have a field with about a thousand lines with many duplicate lines, and I want to delete the duplicates. Seems like this should be simple but I am running around in circles. Can anyone help me with this?
>> 
>> Making the list into an array is the easiest way but as mentioned, it will destroy the original order. If the order is important then you can restore it with a custom sort function...
>> 
> 
> 
> Since order must be maintained, it’s probably faster not to split and sort, and faster not to scan the list repeatedly using lineOffset or contains.
> You could do it like this:
> 
> command removeDuplicates pDelimitedList, pDelimiter
>   local tArray, tList
>   set the lineDelimiter to pDelimiter
>   repeat for each line tLine in pDelimitedList
>      if not tArray[tLine] then -- i.e., if this line hasn't appeared already, then ...
>         put true into tArray[tLine]
>         put tLine & pDelimiter after tList
>      end if
>   end repeat
>   delete last char of tList
>   return tList for value
> end removeDuplicates
> 
> — Dick
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