Defining a variable inside a loop inside a function - r

Question

So I have an assignment, where I have to show the convergence of regression coefficients to a certain value if the observed variable has a measurement error. The idea is to show the convergence depending on the number of observations as well as on the standard deviations of the variables.
I built the following function that should create a matrix with the regression coefficients depending on the number of observations. In a later step I would want to show this in a plot and then in a shiny webapp.
The function is:
Deviation <- function(N, sd_v = 1, sd_u = 1, sd_w = 1){
b_1 <- 1
b_2 <- 2
for ( j in length(1:N)){
v <- rnorm(j, mean = 0, sd_v)
u <- rnorm(j, mean = 0, sd_u)
w <- rnorm(j, mean = 0, sd_w)
X <- u + w
Y <- b_1 + b_2 * X + v
Reg <- lm(Y~X)
if (j==1) {
Coeffs <- matrix(Reg$coefficients)
} else {
Coeffs <- rbind(Coeffs, Reg$coefficients)
}
}
Coeffs <- as.data.frame(Coeffs)
return(Coeffs)
}
Deviation(100)
I always get the error that the variable Coeffs is not defined...
Thanks in advance!

Answer 1

As pointed out in the discussion, one possible solution is to change the length(1:N), to simply 1:Nas written below. This works for me.
Deviation <- function(N, sd_v = 1, sd_u = 1, sd_w = 1){
b_1 <- 1
b_2 <- 2
for ( j in 1:N){
v <- rnorm(j, mean = 0, sd_v)
u <- rnorm(j, mean = 0, sd_u)
w <- rnorm(j, mean = 0, sd_w)
X <- u + w
Y <- b_1 + b_2 * X + v
Reg <- lm(Y~X)
if (j==1) {
Coeffs <- matrix(Reg$coefficients)
} else {
Coeffs <- rbind(Coeffs, Reg$coefficients)
}
}
Coeffs <- as.data.frame(Coeffs)
return(Coeffs)
}
followed by...
Deviation(100)