Dear All, I created a script to calculate averages - two groups: "parcel" and "date" - and, based on these averages, make a graph. The problem is that 'R' does not recognize the first column even if I try to insert one.
A brief example Raw data: Data <- sample(1:100, 30, replace = FALSE, prob = NULL) Date <- rep(c("02/30/2004","03/15/2004", "04/16/2004", "06/14/2004", "07/08/2004"), 6) Parcel <- rep(c("DRY", "CONTROL"),15) Df <- data.frame(Parcel, Date, Data) Res <- tapply(Df$Data, list(Date = Df$Date, Parcel = Df$Parcel), mean) > Res Parcel Date CONTROL DRY 02/30/2004 53.00000 52.33333 03/15/2004 54.00000 67.66667 04/16/2004 54.66667 30.00000 06/14/2004 27.66667 20.00000 07/08/2004 59.00000 38.00000 > colnames(Res) [1] "CONTROL" "DRY" > matplot(Res[,1], Res[,-1], type = "l") ### It does not recognize the colunm "Date". Why? Thanks in advance! Paulo ________________________________________ Paulo M. Brando Instituto de Pesquisa Ambiental da Amazonia (IPAM) Santarem, PA, Brasil. Av. Rui Barbosa, 136. Fone: + 55 93 522 55 38 www.ipam.org.br E-mail: [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html