[R] Odp: creating a new column

[Petr PIKAL]

Hi

without knowing your code, R version and error message it is hard to say 
what is wrong. I think I answered already this or similar question  but 
nevertheless:

If your data are in data frame

ifelse(mm$censoringTime>mm$survivalTime,mm$survivalTime, mm$censoringTime)

gives you a vector of required values

if you have matrix

ifelse(m[,3]>m[,4],m[,4], m[,3])

gives you the same.

Sou you need to add it to your existing structure by cbind() or 
data.frame()

Regards
Petr
petr.pikal at precheza.cz

r-help-bounces at stat.math.ethz.ch napsal dne 07.05.2007 16:27:37:

> hie l would like to create a 6th column "actual surv time" from the 
following data 
> 
>   the condition being
>   if  censoringTime>survivaltime then actual survtime =survival time
>   else actual survtime =censoring time
> 
>   the code l used to create the data is
> 
>        s=2
>        while(s!=0){ n=20
>          m<-matrix(nrow=n,ncol=4)
> colnames(m)=c("treatmentgrp","strata","censoringTime","survivalTime")
>         for(i in 1:20) 
m[i,]<-c(sample(c(1,2),1,replace=TRUE),sample(c(1,2),
> 1,replace=TRUE),rexp(1,.007),rexp(1,.002))
>         m<-cbind(m,0)
>          m[m[,3]>m[,4],5]<-1
>          colnames(m)[5]<-"censoring"
>       print(m)
>        s=s-1
>           treatmentgrp strata censoringTime survivalTime censoring
>    [1,]             1      1       1.012159    1137.80922         0
>    [2,]             2      2      32.971439     247.21786         0
>    [3,]             2      1      85.758253     797.04949         0
>    [4,]             1      1      16.999171      78.92309         0
>    [5,]             2      1     272.909896     298.21483         0
>    [6,]             1      2     138.230629     935.96765         0
>    [7,]             2      2      91.529859     141.08405         0
> 
> 
>   l keep getting an error message when i try to  create the 6th column
> 
> 
> 
> 
> 
> ---------------------------------
> 
> 
>    [[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.