(1) I have a master data frame that reads ClientID |date |value
(2) I also have a control data frame that reads Client ID| Min date| Max date| control parameters The control data set may not have all client IDs . I want to use the control data frame on the master data frame to remove client IDS that don't exist in the control data set and for those that do, remove dates outside the required range. (3) We can either put the control parameters on all rows corresponding to a client ID or look it up from the control data frame (4) The basic function call looks like do.something(df,control parameters) where df is the subset of the master data set that corresponds to a single client with unwanted dates removed and the control parameters pertain to that client. Any help would be appreciated. ______________________________________________ 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.