R interview questions part 33
R interview questions part 33
Take as many assements as you can to improve your validate your skill rating
Total Questions: 20
1. Point out the correct statement :
Correct Answer is : Using system.time() allows you to test certain functions or code blocks to see if they are taking excessive amounts of time
2. R comes with a ________ to help you optimize your code and improve its performance.
Correct Answer is : debugger
3. The _______ function computes the time (in seconds) needed to execute an expression.
Correct Answer is : system.time()
4. Point out the correct statement :
Correct Answer is : Rprof() keeps track of the function call stack at regularly sampled intervals
5. system.time function returns an object of class _______ which contains two useful bits of information.
Correct Answer is : proc_time
6. _________ time is time charged to the CPU(s) for the R expression.
Correct Answer is : elapsed
7. The elapsed time may be ________ than the user time if your machine has multiple cores/processors
Correct Answer is : smaller
8. Parallel processing is done via __________ package can make the elapsed time smaller than the user time.
Correct Answer is : parallel
9. You can time ________ expressions by wrapping them in curly braces within the call to system.time().
Correct Answer is : longer
10. The profiler can be turned off by passing _________ to Rprof().
Correct Answer is :
11. Point out the correct statement :
Correct Answer is : At each line of the output, the profiler writes out the function call stack
12. How many methods exist for normalizing the data ?
Correct Answer is : two
13. _______ divides the time spend in each function by the total run time
Correct Answer is : “by.total”
14. Point out the correct statement :
Correct Answer is : By default, the profiler samples the function call stack every 0.02 seconds
15. Which of the following function actually fits the linear model ?
Correct Answer is : lm.fit()
16. _________ time is time charged to the CPU(s) for the R expression.
Correct Answer is : elapsed
17. The final bit of output that summaryRprof() provides is the ______ interval and the total runtime.
Correct Answer is : sampling
18. Which of the following statement gives sampling interval ?
Correct Answer is : $sampling.time
19. Which of the following code is not profiled ?
Correct Answer is : C
20. The ________ function takes an arbitrary number of arguments and concatenates them one by one into character strings.
Correct Answer is : copy()
