I have this data :
I created a column "fusion" that combine "quadrat" and "année" and I would like to select only unique value of "fusion" in order to have corresponding values in "densité".
There is the function unique() but it list the unique values of "fusion" and don't select the entire row in order to do a new data table with "densité"'s values.
I would like to have the same table but without the duplicates so :
quadrat site gestion densité année ... fusion
A1 A Abandon 1.70 2000 2000_A1
A2 A Abandon 1.35 2000 2000_A2
A3 A Abandon 1.70 2000 2000_A3
I hope I've been clear
Thanks for your help,