Hello!
I have an maybe a to a simple question but I cant get it right.
I have a dataframe with in one column an id-variable and in another a
year-variable. One id-number can occur several years.
I have sorted the dataframe on id then on year so the same id-number is sorted
by year with the first occurens at top.
Now I want to make a subset of this dataframe with just the first year the
id-number occur, so the first case of every id.
Id Year
123456 2001
123456 2002
123456 2003
655432 2001
655432 2002
655432 2003
Is there a simple command I can do?
Thanks!
Jojje
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