For loop storage of output data - r

Question

I am trying to store the output data from the forloop in the n.I matrix at the end of the code, but I am certain that something is wrong with my output matrix. It is giving me all the same values, either 0 or 1. I know that print(SS) is outputting the correct values and can see that the forloop is working properly.
Does anyone have any advice on how to fix the matrix, or any way that I am able to store the data from the forloop? Thanks in advance!
c=0.2
As=1
d=1
d0=0.5
s=0.5
e=0.1
ERs=e/As
C2 = c*As*exp(-d*s/d0)
#Island States (Initial Probability)
SS=0
for(i in 1:5) {
if (SS > 0) {
if (runif(1, min = 0, max = 1) < ERs){
SS = 0
}
}
else {
if (runif(1, min = 0, max = 1) < C2) {
SS = 1
}
}
print(SS)
}
n.I=matrix(c(SS), nrow=i, ncol=1, byrow=TRUE)

Answer 1

The efficient solution here is not to use a loop. It's unnecessary since the whole task can be easily vectorized.
Z =runif(100,0,1)
as.integer(x <= Z)
#[1] 0 0 0 0 1 1 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 1 0 0 1 0 0 1 1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0
#[70] 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0

Answer 2

you can save them in a list. Not very efficient but gets the job done.
list[[1]] indicates the first element saved in a list if you want to retrieve it.
list_pos <- list() # create the list out of the for loop
for(i in 1:100) {
c=0.10 #colonization rate
A=10 #Area of all islands(km^2)
d=250 #Distance from host to target (A-T)
s=0.1 #magnitude of distance
d0=100 #Specific "half distance" for dispersal(km)
C1 = c*A*exp(-d/d0) #Mainland to Target colonization
Z =runif(1,0,1)
x <- C1*A
if(x <= Z) {
list_pos[[i]] <- print("1") # Here you can store the 1 results.print is actually not necessary.
}
if(x >= Z){
list_pos[[i]] <- print("0") # Here you can store the 0 results.print is actually not necessary.
}
}