You have not told us enough about your data. If your data is an array of strings with comma separated fields, The reference to FAQ4 is probably correct. More likely, you have an array of array references. Each reference refers to an anonymous array of the form you show. Now, "duplicate" is less clear because duplicate arrays and duplicate references are not the same thing.
In any case, you probably mean to remove all but one a duplicated entry, making it unique. You could mean to remove all duplicate entries, leaving only those that were already unique.