Hi: Here's one approach, converting the sub-data frames to zoo objects:
# Function to convert one of the data frames to a zoo object makezoo <- function(df) { require(zoo) date <- as.Date(df[, 1], format = '%m/%d/%y') with(df, zoo(freq, date)) } library(zoo) # Split the data frame by condition: tt <- split(x.df[, -2], x.df$cond) # > str(tt[[1]]) # 'data.frame': 5 obs. of 2 variables: # $ date: Factor w/ 5 levels "04/01/09","04/02/09",..: 1 2 3 4 5 # $ freq: int 12 11 10 13 6 # Apply the makezoo function to each component of the list tt: (tser <- lapply(tt, makezoo)) $Fever 04/01/09 04/02/09 04/03/09 04/04/09 04/05/09 12 11 10 13 6 $Rash 04/01/09 04/02/09 04/03/09 04/04/09 04/05/09 6 10 9 10 8 $Respiratory 04/01/09 04/02/09 04/03/09 04/04/09 04/05/09 12 9 6 11 11 # Check that the classes are OK: > sapply(tser, class) Fever Rash Respiratory "zoo" "zoo" "zoo" You can then do things like plot.ts, for example: lapply(tser, plot.ts) HTH, Dennis On Wed, Jun 2, 2010 at 8:37 AM, Erin Hodgess <erinm.hodg...@gmail.com>wrote: > Dear R People: > > I have the following data frame: > > > x.df > date cond freq > 1 04/01/09 Fever 12 > 2 04/02/09 Fever 11 > 3 04/03/09 Fever 10 > 4 04/04/09 Fever 13 > 5 04/05/09 Fever 6 > 6 04/01/09 Rash 6 > 7 04/02/09 Rash 10 > 8 04/03/09 Rash 9 > 9 04/04/09 Rash 10 > 10 04/05/09 Rash 8 > 11 04/01/09 Respiratory 12 > 12 04/02/09 Respiratory 9 > 13 04/03/09 Respiratory 6 > 14 04/04/09 Respiratory 11 > 15 04/05/09 Respiratory 11 > > > > I would like to generate 3 time series (or zoo objects or its); one > for Fever, one for Rash, and one for Respiratory. There are 2 > questions here, please: > a. How do I generate the series, please? > b. Which is best, time series, zoo objects, or its objects, please? > > Thanks, > Erin > > > -- > Erin Hodgess > Associate Professor > Department of Computer and Mathematical Sciences > University of Houston - Downtown > mailto: erinm.hodg...@gmail.com > > ______________________________________________ > 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. > [[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.