title: R survival analysis coxph call multiple column
body: <p>I am trying to use <code>coxph</code> function under <code>survival</code> package. Normally it will be called as: </p>
  
  <p><code>coxph(Surv(time,event) ~ age+gender+salary, data=THEDATA)</code>. </p>
  
  <p>However, I have multiple columns in  <code>THEDATA</code>. How can I call them easily? E.g, I want to build Cox model based on variables on column 8 - 12. Compared with doing </p>
  
  <p><code>coxph(Surv(THEDATA$time,THEDATA$event）~ THEDATA[,8] + THEDATA[,9] + THEDATA[,10] + THEDATA[,11] + THEDATA[,12])</code></p>
  
  <p>, how to use a more efficient code to do the job?</p>