繪圖倖存者

Question

我是R新手，想要繪製survfit生存曲線。

在與survfit對象玩耍，我發現，我得到2個不同的地塊爲以下幾點：

library(survival) 

#example survfit object 
mysurvfit <- survfit(Surv(time, status)~1, data=aml) 

#default survfit plot, survival curve with upper & lower conf intervals 
plot(mysurvfit, mark.time=FALSE, conf.int=TRUE) 

#create another curve by accessing surv, upper, lower 
#(I'd expect this to produce the same as above, but it doesn't) 
lines(mysurvfit$surv, col="blue",lty=1) 
lines(mysurvfit$upper, col="blue",lty=2) 
lines(mysurvfit$lower, col="blue",lty=2) 

爲什麼這些曲線有什麼不同？我對倖存對象錯過了什麼？

Answer 1

你缺少time變量

嘗試

plot(mysurvfit, mark.time=FALSE, conf.int=TRUE) 
lines(mysurvfit$surv ~ mysurvfit$time, col="blue",lty=1) 
lines(mysurvfit$upper ~ mysurvfit$time, col="blue",lty=2) 
lines(mysurvfit$lower ~ mysurvfit$time, col="blue",lty=2) 

它看起來像