title: what's wrong with my while loop code in R?
body: <p>I want to using while loop in R.</p>
  
  <p>I want to repeat loop until evt>1 and cpr>0, but it doesn't work.</p>
  
  <p>work_f is function of generating numbers.</p>
  
  <pre><code>if((evt&gt;1)&amp;&amp;(cpr&gt;0)){
  work&lt;-work[order(work$z),]
  obs&lt;-c(1:length(work$z))
  work&lt;-cbind(work,obs)
    } else {
   while((evt&gt;1)&amp;&amp;(cpr&gt;0)) {
    j&lt;-j+1
    seed&lt;-settings*1000+h+j     
  
    work_f(studysize = studysize,beta=beta,cutpoint = cutpoint,settings = settigns,p=p,alpha = alpha)
  
    evt&lt;-data.frame(ftable(work$event))
    evttr&lt;-data.frame(evt=numeric(1),cpr=numeric(1),csr=numeric(1))
    if (p==0) {
      evttr$evt&lt;-evt$Freq[1]; evttr$cpr&lt;-evt$Freq[2]; evttr$csr&lt;-0
    }else {
      evttr$evt&lt;-evt$Freq[2]; evttr$cpr&lt;-evt$Freq[3]; evttr$csr&lt;-evt$Freq[1]
    }
    evttr[is.na(evttr)]&lt;-0
    evt&lt;-as.numeric(evttr$evt); cpr&lt;-as.numeric(evttr$cpr)
  
    if((evt&gt;1)&amp;&amp;(cpr&gt;0)){
      work&lt;-work[order(work$z),]
      obs&lt;-c(1:length(work$z))
      work&lt;-cbind(work,obs)
    }
   }
  } 
  </code></pre>
  
  <p>What's wrong?</p>