[R] Lines for plot (Sweave)

Don MacQueen macq at llnl.gov
Fri Jul 1 22:21:52 CEST 2005

You can use:

   lines(x[!is.na[stu.vector], stu.vector[!is.na(stu.vector)], lty=1, 


At 1:43 PM -0400 7/1/05, Doran, Harold wrote:
>Dear List:
>I am generating a series of plots iteratively using Sweave. In short, a
>dataframe is subsetted row by row and variable graphics are created
>conditional on the data in each row. In this particular case, this code
>ends up generating 17,000 individual plots.
>In some cases, all student data (this is working with student
>achievement data) are available and my code below works very well in the
>sense that a line connects all points. However, in some cases there are
>missing data and I need to modify my code so that lines are connected
>through all points even when data are missing.
>Here is a snip of relevant code. In the actual program, the data in
>stu.vector and avg.vector are obtained from the dataframe as the
>programs loops through each row.
>stu.vector<-c(2500, 2510,   NA , 2600)
>avg.vector<-c(2635, 2589, 2628, 2685)
>x <- c(0,1,2,3)
>graph.min <- min(stu.vector,avg.vector ,na.rm=TRUE)-150
>graph.max <- max(stu.vector,avg.vector ,na.rm=TRUE)+150
>plot(x, stu.vector, ylim=c(graph.min,graph.max),  xlab=" ", ylab="Scaled
>Score", xaxt='n', pch=2, col='blue', main="Math Growth Rate")
>points(x, avg.vector, pch=1, col='red')
>lines(x, stu.vector, lty=1, col='blue')
>lines(x, avg.vector, lty=3, col='red')
>If the NA did not exist in the object stu.vector then all points would
>be connected with lines. However, in some cases data are missing and I
>need to connect the data in stu.vector with lines. So in this case, the
>line would connect points 1 and 2, and then 2 and 4 even though point 3
>is missing.
>Can anyone suggest how I might do this?
>	[[alternative HTML version deleted]]
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Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA

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