I highly recommend browsing the Categorized Questions and Answers section here. It's a great way to accumulate a lot of useful knowledge quickly. The QandASection: arrays section includes How do I find if an array has duplicate elements, if so discard it?.
Caution: Contents may have been coded under pressure.

In reply to Re: removing duplicate entries from an array by Roy Johnson
in thread removing duplicate entries from an array by Anonymous Monk

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