[R] Re: none

[Peter Dalgaard BSA]

"Troels Ring" <tring at mail1.stofanet.dk> writes:

> Dear friends.
> 
> I wanted to reproduce a sheet of paper useful for plotting the reciprocal of some biochemical variable (creatinine) over time (Bleyer Am J Kidney Dis 34:576-578,1999). Time on X axis with units years and months. On Y axis, 1/creatinine, but with the original creatinine value indicated - to make it easier for people to use it. When using the graph, the linear decrease in 1/crea over time will be useful for managing patients. Here is what I came up with, but how do I configure the Y axis with the natural values 40-2000 umol/l alongside their reciprocal representation, so that 1/crea will be a stright line ?
> 
>  x <- NA
>  y  <- NA
>  plot(x,y,xlim=c(0,10),ylim=c(40,2000))
>  grid(nx=10,ny=10,col="black",lty="solid")
>  grid(nx=120,ny=10,col="black",lty="dotted")

Something like this, perhaps:

x<-y<-NA
plot(x,y,xlim=c(0,10),ylim=1/c(2000,40), axes=F)
box()
axis(1)
pretty.y<-c(40,50,60,70,100,200,500,2000)
axis(2,at=1/pretty.y,labels=rev(pretty.y),las=2)
axis(4) # for comparison

(The rev() is necessary in both 0.65.x and my version of 0.90.0 pre, but
it looks like a bug, at= and labels= should match up)

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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