/    /  R programming – Interview questions Part 4

1. How impossible values are represented in R?

Answer: Impossible values are represented as NaN in R.


2. Which command is used for storing R object into a file?

Answer:  Save command is used for storing R objects into a file.

Syntax: >save(z,file=”z.Rdata”)


3. Which command is used for restoring R object from a file?

Answer: load command is used for storing R objects from a file.

Syntax: >load(”z.Rdata”)


4. What is the use of coin package in R?

Answer: Coin package is used to achieve the re randomization or permutation based statistical tests.


5. Which function is used for sorting in R?

Answer: order() function is used to perform the sorting.


6. What is the use of tapply?

Answer:  IOS-6.1.3


7. When the application object does not handle an event, and then happens?

Answer: The event will be dispatched to your delegate for processing.


8. In what way app specific objects store the app contents.

Answer: The app specific objects are Data model objects that store app’s contents.


9. Explain the purpose of using UIWindow object?

Answer:  UIWindow object coordinates the one or more views presenting on the screen.


10. Tell me the super class of all view controller objects.

Answer:  UIView Controller class.