Im sure a question like this has been asked before. But Im struggling to find an answer (and to even word the question clearly).
If I have 2 variables, I want to apply a function to each pair of these variables, where the function depends on a third variable. For example,
If I have some data that looks like this:
x <- c(1:4)
y <- c(1,2)
n <- seq(1,200, length.out = 100)
Now, imagine I want to apply rnorm
to each of the pairs of x
and y
, where y
would be my mean and x
would be the standard deviation. But I want to loop through each of these pairs where each value of n
would be my number of observations.
So for example, I was trying a nested loop... the below example doesn't work, but I hope it illustrates what Im trying to achieve:
for(i in 1:2){
for(j in 1:4){
for(k in 1:length(n)){
ans[] <- rnorm(n[k], y[i], x[j])
}
}
}
Any suggestions as to how I could achieve this?
CodePudding user response:
using expand.grid
z = expand.grid(n,x,y)
apply(z, 1, function(i) rnorm(i[1], i[2], i[3]))