Matthew Green Matthew Green - 21 days ago 7
R Question

For loop storage of output data

Is there an efficient/good way to store data coming out of a for loop? I know the storage function can be useful but it doesn't seem to apply to my 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) {
print("1")
}
if(x >= Z){
print("0")
}
}

Answer

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