[R] Problems trying to generate a prime factor vector

[Kevin Wright]

Hi,

I am very new to 'R' and am trying to write an R function which returns the
prime factors of a given number(n)

Unfortunately, the function only works for very small numbers, if for
example I pass 18 to the function
a mysteriously long vector is returned. I have not been able to find where
or why this is happening.
I know I've done something wrong. I've tried using debugging statements.
Sometimes the
currentPrime variable seems to become some sort of array?!


can you help?


library(gmp)


#passing 18 returns: 2 1 0 0 0 1 0 0 0 1 0 0 0 3 0 0 0 1 0 0 0 1 0 0 0 1 0
0 0 3 0 0 0
# expected: 2 3 3
getPrimeFactors = function(n){
   primeList <- c()

   if( isprime(n) ){
      primeList <- append(primeList,n)
      return (primeList)
   }

   currentPrime <- 2

   while(TRUE){
      # Check if input is divisible by the current prime
      if(n %% currentPrime == 0){
         cat(sprintf("the number %f is divisible by %f\n", n,
currentPrime))
         n = n%/%currentPrime

         cat(sprintf("value of n is %f\n", n))

         cat(sprintf("current prime :%f\n", currentPrime))
         primeList = append(primeList,currentPrime)
        # print(c("list contents:", primeList))


         currentPrime = 2

         if( isprime(n)){

              primeList = append(primeList, n)
              return (primeList)

         }

      }
      else{
         cat(sprintf("the number %f is NOT divisible by %f\n", n,
currentPrime))
         #cat(sprintf("current prime before is: %f\n", currentPrime))
         #print(c("current prime before:", currentPrime))
         currentPrime = nextprime(currentPrime)
         #cat(sprintf("current prime after is: %f\n", currentPrime))
         #print(c("current prime after:", currentPrime))

      }



   }




}






}

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