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[Ray Horsley]

Greetings Listers,

I'm working with large amounts of data, say 50,000 tab delimited lines, 
where the 4th item in each line is the same for every 20 or so lines.  
Does anybody have a fast way of determining how many unique 4th items 
there are in the 50,000 lines?

A repeat loop examining each line is certainly out of the question, and 
I've tried using various functions such as itemOffset after sorting 
ascending and descending, but this too is turning out to be kind of 
slow.

Thanks,


Ray Horsley
Developer, LinkIt! Software