Use result of previous loop as input for next loop

Question

I have the code below, which seems to accomplish what I'm trying to do but also throws the error output shown below the code. What I'm trying to do, is run through the loop the first time with x = 1, then for each time the loop runs after that I want x = y, the result of the previous loop. I always fumble with loops so any tips are greatly appreciated.

Code:

for(i in 1:5)
{ 
 if(i=1)
 {
 x<-1
 }
 else
 {
 x<-y
 }
 y<-x*i
 y
 }


ERRORS:

 for(i in 1:5)
+ { 
+   if(i=1)
Error: unexpected '=' in:
  "{ 
    if(i="
   >   {
   +   x<-1
   +   }
    >   else
   Error: unexpected 'else' in "  else"
   >   {
   +   x<-y
  +   }
   >   y<-x*i
   >   y
   [1] 25
   > }
   Error: unexpected '}' in "}"

Answer 1

Here is your code re-written with slightly clearer syntax

for (i in 1:5) {
    if (i == 1) {
        x <- 1
    } else {
        x <- y
    }
    y <- x * i
}

Or even better syntax.

for (i in 1:5) {
    x <- ifelse(i == 1, 1, y)
    y <- x * i
}