Question

Possible Duplicate:
General suggestions for debugging R?

When debugging, I would often like to know the value of a variable used in a function that has completed executing. How can that be achieved?

Example:

I have function:

MyFunction <- function() {
    x <- rnorm(10) # assign 10 random normal numbers to x
    return(mean(x))
}

I would like to know the values stored in x which are not available to me after the function is done executing and the function’s environment is cleaned up.

Answer 1

You mentioned debugging, so I assume the values are not needed later in the script, you just want to check what is happening. In that case, what I always do is use browser:

MyFunction <- function() {
    browser()
    x <- rnorm(10) # assign 10 random normal numbers to x
    return(mean(x))
}

This drops you into an interactive console inside the scope of the function, allowing you to inspect what is happening inside.

For general information about debugging in R I suggest this SO post.