[R] plotting a point graph with data in X-axis

Adaikalavan Ramasamy ramasamy at cancer.org.uk
Wed May 9 03:21:17 CEST 2007

R understands only numerical and Date class values for axis. So either

a) plot them using the sequence 1, ..., 32 and then explicitly label 
them. Here is an example:

  n <- length(year.month)
  plot( 1:n, freq, xaxt="n")
  mtext( text=year.month, side=1, at=1:n, las=2 )

b) or create the dates in Date format. This option is preferable if the 
dates were varying unequally.

  x <- seq( as.Date("2000-05-01"), as.Date("2002-12-01"), by="1 month" )
  plot(x, simulation$freq)

BTW, you could also have created year.month via
   paste( rep( 2000:2002, c(8,12,12) ),
          formatC( c(5:12,1:12,1:12), width=2, flag="0" ) , sep="_" )

Regards, Adai

Milton Cezar Ribeiro wrote:
> Dear all,
> I have two data frame, on with a complete list of my field survey with frequency data of a sample species. This data frame looks like:
> simulation<-data.frame(cbind(my.year=c(rep(2000,8),rep(2001,12),rep(2002,12)),my.month=c(5:12,1:12,1:12)))
> simulation$year.month<-paste(simulation$my.year,"_",ifelse(simulation$my.month>=10,simulation$my.month,paste("0",simulation$my.month,sep="")),sep="")
> simulation$freq<-sample(1:40,32)
> attach(simulation)
> plot(year.month, freq)
> As you can see, I have a collumn with the year and month of my samples, and a freq variable with simulated data. I would like to plot this data but when I try to use the plot showed above, I get a error message. 
> After bypass this problem, I would like add points in my graph with simulated data for only a random number of survey month, but I need that the full range of surveys be kept on the X-axis. Just to simulate a sample I am using:
> simulation.sample<-simulation[sample(1:length(year.month),8, replace=F),]
> simulation.sample$freq<-sample(1:40,8)
> Any ideas?
> Kind regards
> Miltinho
> __________________________________________________
> 	[[alternative HTML version deleted]]
> ______________________________________________
> R-help at 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
> and provide commented, minimal, self-contained, reproducible code.

More information about the R-help mailing list