.
That's what I would recommend. The second method can be implemented
directly:
bysort X : drop if _N == 1
so that the extra variable is dispensable.
Eva Poen
008/5/2 Stefano Costalli <[email protected]>:
> I have a variable with about 25.000 observations and many unique
values. I need to drop the unique values, but I can't browse the whole
data set to search for each unique value individually.
I'm not quite I understand. Do you have one variable X in your data,
and within X there are some duplicates, and you want to drop
everything that is unique? In this case you can either use
duplicates tag X, gen(tag)
drop if tag==0
or, equivalently,
bysort X: gen drop = _N
drop if drop==1
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