Debugging tools in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the browser() function in R?

The browser() function pauses the execution of R code and allows you to inspect variables and step through the code interactively to find bugs.

beginner

How does traceback() help in debugging R code?

traceback() shows the sequence of function calls that led to an error, helping you understand where the problem happened.

intermediate

What is the use of debug() in R?

debug() marks a function so that when it is called, R enters the browser mode inside that function, allowing step-by-step execution.

intermediate

Explain the difference between browser() and debug().

browser() is placed manually inside code to pause execution at that point, while debug() is used to mark a function so that every time it runs, it pauses at the start.

advanced

What does the recover() function do in R debugging?

recover() allows you to choose which environment to enter after an error occurs, letting you inspect the state of the program at different call levels.

Which R function shows the call stack after an error?

A traceback()

B browser()

C debug()

D recover()

traceback() prints the sequence of calls that led to an error, helping locate the problem.

What happens when you use debug() on a function?

A The function runs normally without interruption

B Execution pauses at the start of the function for step-by-step debugging

C The function is skipped

D An error is thrown immediately

debug() causes R to pause inside the function so you can step through the code.

Which debugging tool lets you interactively inspect variables at any point in your code?

A traceback()

B debug()

C recover()

D browser()

browser() pauses execution and lets you check variables and run commands interactively.

How does recover() improve error handling?

A It automatically fixes errors

B It prevents errors from occurring

C It lets you choose which environment to inspect after an error

D It logs errors to a file

recover() allows you to select the call frame to debug after an error happens.

When would you use browser() instead of debug()?

A To pause execution at a specific line inside a function

B To debug all calls to a function

C To print the call stack

D To recover from an error

browser() is placed at a specific spot in code to pause there, unlike debug() which pauses at function start.

Describe how you would use debug() and browser() to find a bug in an R function.

Think about when you want to pause the whole function vs a specific spot.

Explain the role of traceback() and recover() in understanding errors in R.

One shows the path, the other lets you explore the problem.