Since someone's already fixed the OP's code to do what was intended, I'll put in how I might have written this.

<Reveal this spoiler or all in this thread>

Unlike another short solution posted elsewhere, this keeps the lines in their original order while filtering out the duplicates.

In reply to Re: finding unique items in an array, from a text file by kyle
in thread finding unique items in an array, from a text file by spazmospazmo

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