creating list of outputs from a function - r

Question

I would like to know how can I list the outputs of my function (it prints out vectors) so that I am able to know how many steps did it require until finding the optimal solution.
I have the following code and am just wondering what should I do at the end so that when printing out the vectors, it enumerates them one at a time as well. I am new to Rstudio and do see that some operations that have to do with matrices are not common in other programming languages.
I should say that I have already defined another function such as "gradient", but my concern is about the enumeration of the outputs for this particular function.
Sd=function(b0,epsilon=1e-5){
while (norm(gradient(b0))>epsilon) {
num1=(t(b0)%*%Q%*%gradient(b0)-t(y)%*%X%*%gradient(b0))/(t(gradient(b0))%*%Q%*%gradient(b0))
num2=norm(num1)
step=num2*gradient(b0)
b0=b0-step
print(t(b0))
}
}
Thank you for any help I can get.

Answer 1

Here's a generic answer that will show you how to approach this. Without access to your custom functions I can't give a more direct answer. It's generally helpful to give a minimal reproducible example.
That said, my basic suggestion is to use a counter variable, increment it once each loop, and include that in your printed output.
Here's a simplified example that's based on your code, but the only operation we're doing is taking repeated square roots. Note that the arrow operator <- is the best practice for assigning values. (I promise you get used to it!)
# set up a generic function for this minimal example
get_value <- function(x){
return (sqrt(x))
}
my_function <- function(b0, epsilon = 1.1){
# set up a counter variable
i <- 0
# our main loop
while (get_value(b0) > epsilon) {
# increment the counter
i <- i + 1
# do calculations
num1 <- get_value(b0)
# update our current solution
b0 <- num1
# print a message to the console with the counter and the value
message(paste0("Iteration: ",i,"\n",
"b0: ", b0))
}
# print a final message to the console when we stop
message(paste0("Final Iteration: ",i,"\n",
"Final b0: ", b0))
}
my_function(2)