ABSTRACT
Chapter 22 teaches you the art and science of debugging, starting with a general strategy, then following up with specific tools.
I’ll show the tools provided by both R and the RStudio IDE. I recommend using RStudio’s tools if possible, but I’ll also show you the equivalents that work everywhere. You may also want to refer to the official RStudio debugging documentation which always reflects the latest version of RStudio.
NB: You shouldn’t need to use these tools when writing new functions. If you find yourself using them frequently with new code, reconsider your approach. Instead of trying to write one big function all at once, work interactively on small pieces. If you start small, you can quickly identify why something doesn’t work, and don’t need sophisticated debugging tools.
“Overall approach” outlines a general strategy for finding and fixing errors. “Locating errors” introduces you to the traceback() function which helps you locate exactly where an error occurred. “Interactive debugger” shows you how to pause the execution of a function and launch environment where you can interactively explore what’s happening. “Non-interactive debugging” discusses the challenging problem of debugging when you’re running code non-interactively. “Non-error failures” discusses a handful of non-error problems that occassionally also need debugging.
