Function Outputting Two outputs where 1 is required

Question

My code is currently taking 4 dice rolls and changing the values to 8 if they can be summed to 8.

My function is able to correctly change (1,3,4,5) to (5,8) as required. However I run into a problem if my Dice roll is ( 1,2,6,5) for example as It is possible for two combinations of 8 to be made. eg (6,2 could be used or 1,2,5). I need my code to only output One of these solutions and I can't grasp how to do this.

   target2 <- function(x)
   {
   roll <- (x)
   library(dplyr)

    comboes <- Reduce( f=append, lapply( 2:4, function(m)combn(x=roll, m=m) %>% as.data.frame %>% 
    as.list  ) )

    i.is.eight <- which( sapply( comboes, sum ) == 8 )

    check <- c(i.is.eight) 

    if((length(check) == 0))
  return(roll)
   else if( length(check) >= 1 ){
   lapply( i.is.eight,function(i) {
  
  roll.i <- comboes[[i]]
  
  ## base is the dice that did not take part in the sum
  base <- roll
  for( r in roll.i ) {
    base <- base[ -match( r, base ) ]
  }
  
  
  answer <- c( base, 8 )
  

  return(answer)
  
}) %>% unique
} 
}

 (   x <-sample(1:6, 4, replace=TRUE))
  target2(x)

I get my code isn't the clearest so happy to explain. Any Help would be greatly appreciated.

Answer 1

You could just store all answers in a list and just return the first element of that list.

target2 <- function(x)
{
  roll <- (x)
  library(dplyr)
  
  comboes <- Reduce( f=append, lapply( 2:4, function(m)combn(x=roll, m=m) %>% as.data.frame %>% 
                                         as.list  ) )
  
  i.is.eight <- which( sapply( comboes, sum ) == 8 )
  
  check <- c(i.is.eight) 
  
  if((length(check) == 0))
    return(roll)
  else if( length(check) >= 1 ){
    answers <-lapply( i.is.eight,function(i) {
      
      roll.i <- comboes[[i]]
      
      ## base is the dice that did not take part in the sum
      base <- roll
      for( r in roll.i ) {
        base <- base[ -match( r, base ) ]
      }
      
      
      answer <- c( base, 8 )
      
      
      return(answer)
      
    }) 
    return(answers[[1]])
  } 
}

(   x <-sample(1:6, 4, replace=TRUE))
target2(x)