I'm new to R and cannot make plotting work as desired. The problem is that R seems to draw the same four lines over and over again, redundantly. The details of the case I'm having are as follows.I have a dataset:> str(dataset)'data.frame':   57641 obs. of  3 variables: $ duration : num  3 8 7 2 4 8 2 2 8 8 ... $ graduated: logi  FALSE TRUE TRUE FALSE FALSE TRUE ... $ group    : num  651 651 671 671 651 651 651 651 651 651 ...Then, I fit a Cox proportional hazards regression model to it:survObj <- Surv(time = dataset$duration / 2, event = dataset$graduated)model <- coxph(survObj ~ group, data=dataset)Next, following this example, I create a frame that would hopefully group the survival functions by the group number:frame <- data.frame(group = dataset$group)> str(frame)'data.frame':   57641 obs. of  1 variable: $ group: num  651 651 671 671 651 651 651 651 651 651 ...There's four groups in the data:> unique(dataset$group)[1] 651 671 652 681Using this new frame, I create a fitted survival model:fitObjGrouped <- survfit(model, newdata = frame)Finally, I plot the thing:color_set <- rainbow(4)plot(fitObjGrouped, col=color_set)The result has the correct lines, but drawn many times over each other:As you can see, there's two red lines and two blue lines drawn last. They're the correct ones, one for each category, but closer observation reveals that there's a green or other color lines underneath each of them. When converting this to PDF the file size is 273 times larger than what it should be!So the question is: why is R drawing the lines so many many times and how could I achieve correct model fitting and plotting at the same time?Can somebody please help me to better understand the R commands I'm using? Thanks in advance!
R plot(surv(), newdata=...) draws same lines many times - why?
r;survival analysis