Hi All I have these questions and request members expert view on this. a) I have a dataframe (df) with five factors (identity variables) and value (measured value). The id variables are Year, Country, Commodity, Attribute, Unit. Value is a value for each combination of this. I would like to get just the unique combination of Commodity, Attribute and Unit. I just need the unique factor combination into a dataframe or a table. I know aggregate and subset but dont how to use them in this context. b) Is it possible to inclue non- aggregate columns with aggregate function say in the above case > aggregate(Value ~ Commodity + Attribute, data = df, FUN = count). The use of count(Value) is just a round about to return the combinations of Commodity & Attribute, and I would like to include 'Unit' column in the returned data frame? c) Is it possible to subset based on unique combination, some thing like this. > subset(df, unique(Commodity), select = c(Commodity, Attribute, Unit)). I know this is not correct as it returns an error 'subset needs a logical evaluation'. Trying various ways to accomplish the task. will be grateful for any ideas and help Regards, SNVK
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