I have a data frame that contains data for multiple (seven) subjects. Each subject is represented by a new value of PID. I would like to plot the data for all seven subjects. For each subject I want to plot a line showing CT as a function of Nit, with the dots for each subject joined. I have tried to accomplish this using the by function. I get an error message, Error in match.fun(panel) : 'xx[, "CT"]' is not a function, character or symbol I have no idea what is causing the error, nor how to correct the error, nor how to get the dots for each point be connected by a line.
Any help would be appreciated! PID <- c( 1 , 1 , 1 , 1 , 2, 2, 2, 2, 3 , 3 , 3 , 3 , 4 , 4, 4, 4 , 5, 5, 5, 5, 6, 6, 6, 6, 7 , 7 , 7 , 7) Nit <- c(NA , -9.23,-11.61,-7.88,NA,NA,NA,NA,-5.59, 0.73,-10.55, -9.13, 3.67, NA, NA,-13.26,NA,NA,NA,NA,NA,NA,NA,NA,-9.36, 5.08, -5.73, 2.02) CT <- c(544,459 ,432 ,NA ,NA,NA,NA,NA,1398 ,1287 ,1049 , NA ,543 ,474,507,NA ,NA,NA,NA,NA,NA,NA,NA,NA,992 ,992 ,1078 ,NA) xx <- data.frame(PID=PID,Nit=Nit,CT=CT) xx by(xx,as.factor(xx[,"PID"]),plot,xx[,"Nit"],xx[,"CT"]) John David Sorkin M.D., Ph.D. Professor of Medicine Chief, Biostatistics and Informatics University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine Baltimore VA Medical Center 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 (Phone) 410-605-7119 (Fax) 410-605-7913 (Please call phone number above prior to faxing) Confidentiality Statement: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
