Question on Merge/Lookup
Perhaps using the R merge() function, possibly twice in succession, will do the job. (merge() does a one to many relational join, but with only two dataframes at at time). Or, there is an R package that lets you use the SQL language on dataframes. I don't recall its name, but a search on R packages should turn it up -- if someone else doesn't provide the name sooner. -Don
At 10:52 AM -0800 1/22/10, GL wrote:
I need to merge three datasets and don't know how. If I were using SQL, I would use df3, look up the characteristics of each date in df1 and the value for each observation in df2. df1 - unique list of Dates and characteristics of those dates Date, YYYYMM, YYYYWW, DOW df2 - the raw data Date, Place, Value df3 - all posibile combinations of Date + Place (via expand.grid(unique(df2$Date),unique(df2$Place)) Date, Place I need to end up with: Date, YYYYMM, YYYYWW, DOW, PLace, Value (plug 0 if combo doesn't exist in raw data). Appreciate any help! -- View this message in context: http://*n4.nabble.com/Question-on-Merge-Lookup-tp1112384p1112384.html Sent from the R help mailing list archive at Nabble.com.
______________________________________________ R-help at 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.
-------------------------------------- Don MacQueen Environmental Protection Department Lawrence Livermore National Laboratory Livermore, CA, USA 925-423-1062