Radu Ban
> i'm cleaning a dataset and i encounter repeated ids. i want
> to keep them
> unique, but the problem is that for some repeated ids the variables
> differ.
> i want to keep just one of the repeated ids. so i'm using:
>
> bysort id: keep if _n == 1
>
> now i would like to know if this will keep the same id whenever the
> program
> is run. or does the ordering change?
>
> sorry for such a basic question but right now i don't have
> access to the manuals.
Jose Luis Negrin Mu�oz
> I have used the following small program to get rid of duplicates
>
> sort ref;
> by ref: gen dup=_n;
> gsort ref -mesini dup;
> drop if dup>1;
>
> where ref is a reference code and mesini is a variable
> related to time
> (1, 2...j); these are the variables I am sorting my data
> by. So I will
> keep only the oldest data with each particular reference code
Two comments:
1. This code appears to keep the most recent
observation within each group, not the oldest.
Another way to do it is
bysort ref (mesini) : keep if _n == _N
2. For general handling of duplicates, there
are several programs, as
. findit duplicate
will show.
Nick
[email protected]
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