Locating errors

The most important tool for finding errors is traceback(), which shows you the sequence of calls (also known as the call stack) that lead to the error.

• Here’s a simple example where f() calls g() calls h() calls i(), which checks if its argument is numeric:

When we run f("a") code in RStudio we see:

If you click “Show traceback” you see:

You read the traceback() output from bottom to top: the initial call is f(), which calls g(), then h(), then i(), which triggers the error.