Hi
r-help-boun...@r-project.org napsal dne 04.01.2011 05:21:25:
> 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.
aggregate(Value, list(Comoditiy, Atribute, Unit), function)
>
> 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?
Hm. Maybe xtabs? But without any example it is only a guess.
>
> 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.
>
Probably sqldf package has tools for doing it but I do not use it so you
have to try yourself.
df[Comodity==something, c("Commodity", "Attribute", "Unit")]
can be other way.
Anyway your explanation is ambiguous. Let say you have three rows with the
same Commodity. Which row do you want to select?
Regards
Petr
> will be grateful for any ideas and help
>
> Regards,
>
> SNVK
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
