Line numbers with errors and warnings?
Le dimanche 02 d?cembre 2012 ? 06:02 -0500, Steve Lianoglou a ?crit :
Hi, On Sun, Dec 2, 2012 at 12:31 AM, Worik R <worikr at gmail.com> wrote:
What I mean is how do I get the R compilation or execution process to spit out a line number with errors and warnings?
Indeed, I often suffer from the same problem when debugging R code too. This is a real issue for me.
As Duncan mentioned already, you can't *always* get a line number. You can, however, usually get enough context around the failing call for you to be able to smoke the problem out.
What are the cases where you cannot get line numbers? Duncan said source()ed code comes with line numbers, but what's the more general rule?
option(error=browser) is a help. But it still does not say what piece of code caused the error.
I typically run with a slightly different setting: R> options(error=utils:::dump.frames) Whenever my script throws an error, after I'm done cursing at it I then wonder where this error happened, so I call: R> traceback() And you'll see the details of the stack that just blew up, starting (or ending, can't remember) with the call itself, then the parent call, and its parent, etc. all the way up to the top most call (likely the line in your script itself). If that's not enough information for me to figure out how to fix the code in my script, I'll then call: R> debugger() and this will then give me (more or less) the same information that `traceback` showed (but in reverse order (which is why I never remember the order of traceback)) and you are asked at what point you'd like to enter the exploded wreckage to explore (via picking a number) ... this way you can poke at the local variables until you see what went wrong.
This is very useful of course to find the problematic function, but quite often I end up wondering what exact command triggered an error. For example, "subscript out of bounds" is hard to match to a precise `[' use in a whole function. Even when using browser(), sometimes you cannot know where you are in the function. So the line number, or the contents of the last line, would be relevant information.
Your error: Error in `[.xts`(x, xsubset) : subscript out of bounds Is suggesting that you are trying to index an `xts` object with an illegal value -- can you find the part in your code that's trying to do this in your own script? You can put a call to `browser()` before that part and explore the value of the subscript vs. the length of your xts object to see what the problem is. If you can't find this point, then take the traceback/debugger route.
This is costing me a lot of time chasing down errors in mine and others code...
... which is typical when your wading in uncharted territory. As you get a better feel of how to resolve these issues, your time-to-fix these things will get better, so ... stay strong.
Of course experience helps, but without the most relevant information (line number) you productivity is always affected... ;-) Regards