[R] 2 KM curves on the same plot

[array chip]

Hi Jim,

I tried the clip() function below, surprisingly it did not work! I read the R help file and feel your script should work. To have a workable example, I used the ovarian dataset in the survival package as an example:

ovarian1<-ovarian
ovarian1$fustat[ovarian$futime>450]<-0
ovarian1$futime[ovarian$futime>450]<-450

ovarian2<-subset(ovarian,futime>450)

fit1 <- survfit(Surv(futime, fustat) ~ rx, data = ovarian1)
fit2 <- survfit(Surv(futime, fustat) ~ rx, data = ovarian2)

plot(fit1, xlim=c(0,1200), col = 1:2)
abline(v=450)
xylim<-par("usr")
clip(450,xylim[2],xylim[3],xylim[4])
lines(fit2, col = 3:4,lty=2)

I can still see that the extra horizontal line on the top. 

Can you or anyone have any suggestion what went wrong?

Thanks,

John


On Tuesday, September 29, 2020, 01:35:48 AM PDT, Jim Lemon <drjimlemon using gmail.com> wrote: 





Hi John,
Perhaps the most direct way would be:

plot(fit1, col=1:2)
xylim<-par("usr")
clip(4,xylim[2],xylim[3],xylim[4])
lines(fit2,col=1:2)

Remember that the new clipping rectangle will persist until you or
something else resets it.

Jim

On Tue, Sep 29, 2020 at 10:34 AM array chip via R-help
<r-help using r-project.org> wrote:
>
> Hello,
>
> Can anyone suggest a simple way to generate a Kaplan-Meier plot with 2 survfit objects, just like this one:
>
> https://drive.google.com/file/d/1fEcpdIdE2xYtA6LBQN9ck3JkL6-goabX/view?usp=sharing
>
> Suppose I have 2 survfit objects: fit1 is for the curve on the left (survtime has been truncated to the cutoff line: year 5), fit2 is for the curve on the right (minimum survival time is at the cutoff line: year 5), but if I do the following:
>
> plot(fit1, col=1:2)
> lines(fit2,col=1:2)
>
> Then I will have an horizontal line on the top that connect from 0 to 4 years, which I do not want that to be drawn (see blue arrow below):
>
> https://drive.google.com/file/d/178mQGlhnaOg9PA-oE-W_W5CtrGD03ljH/view?usp=sharing
>
> Can anyone have a strategy to make this kind of plot happen?
>
> Thanks,
>
> John

>
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