I used the data, aml in survival package in R and computed a survival function by "survfit". Since the result of survfit doesn't show the mean value, I used the following code to print the mean:
print(survfit(Surv(aml1$time,aml1$status)~1),show.rmean=T)
(the data I used is, aml1 <-aml[aml$x="Maintained",])
The code above worked in my friend pc, but not mine. So, I thought about downloading some extra package to use print(...show.rmean=T). But, "print" is basic, so I don't need anything to run print. Then why I can't get the mean value?