如何从给定数字的所有因子的向量中创建素因子向量？

Question

I have generated a list of factors for a given number using a for loop and the append function, which I know is not recommended.

p<-13195
for(i in (p-1):1){
if ((p%%i)==0){
p<-append(p,i)
}
}

I am now trying to report the largest prime factor for this vector, I have used a for loop to print the prime numbers, which is relatively straight forward. (I am missing 1, which could easily be added but I am not interested in that value.)

for (i in p){
if (sum(i/1:i==i%/%1:i)==2){
print(i)
}
}

However, I want to only print the largest prime factor. I have tried several things to do this but they return errors, for example

for (i in p){
 if (sum(i/1:i==i%/%1:i)==2){
 i<-append(1,i)
}
}

Does not work. Plus, I am wary of using the append function. I understand that R is not optimised for loops per say, and I am trying to develop my skills as a programmer so I am looking for alternatives to loops, but I don't mind what the solution is. Ideally I'd like a vector of primes so that I could easily apply

max()

Thank you.

Answer 1

n<-c()
for (i in p){
    if (sum(i/1:i==i%/%1:i)==2){
        n=c(n,i)
    }
}

max<-max(n)