R Programming - Variables MCQ Questions and Answers

R programming is widely used for data manipulation and statistical analysis. Understanding variables is key to working with R efficiently. Variables in R can store a variety of data types, including numeric, character, logical, and complex types. They are essential for storing and manipulating data within programs.

This quiz will test your knowledge of R programming variables, including variable assignment, data types, and built-in functions. Each question will help you better understand how to work with variables in R.

Let’s get started with the following multiple-choice questions (MCQs) to strengthen your understanding of R variables.

1. Which operator is used to assign a value to a variable in R?

a) ==

b) =

c) ->

d) <-

Answer:

d) <-

Explanation:

The <- operator is commonly used in R to assign a value to a variable. While = can also be used, <- is preferred.

2. Which of the following is a valid variable name in R?

a) 1var

b) _variable

c) variable_1

d) var-iable

Answer:

c) variable_1

Explanation:

Variable names in R must begin with a letter or a period, followed by letters, digits, or underscores. variable_1 is the only valid option.

3. What function is used to check the type of a variable in R?

a) class()

b) typeof()

c) checktype()

d) vartype()

Answer:

a) class()

Explanation:

The class() function returns the class of the variable in R, helping you identify its type.

4. Which function in R is used to list all variables in the current environment?

a) ls()

b) list()

c) showvars()

d) vars()

Answer:

a) ls()

Explanation:

The ls() function lists all the variables defined in the current workspace or environment in R.

5. What is the default data type of a variable in R when a number is assigned to it?

a) character

b) integer

c) numeric

d) logical

Answer:

c) numeric

Explanation:

When a number is assigned to a variable, R treats it as numeric by default unless explicitly defined as an integer.

6. How can you remove a variable from the workspace in R?

a) delete()

b) remove()

c) rm()

d) clear()

Answer:

c) rm()

Explanation:

The rm() function in R is used to remove variables from the workspace or environment.

7. Which of the following is NOT a valid data type in R?

a) character

b) string

c) numeric

d) logical

Answer:

b) string

Explanation:

In R, character is used instead of string for text data. Therefore, string is not a valid data type in R.

8. How do you convert a numeric variable to an integer in R?

a) as.numeric()

b) as.integer()

c) convert()

d) as.type()

Answer:

b) as.integer()

Explanation:

The as.integer() function is used to convert numeric variables to integers in R.

9. How can you check if a variable is numeric in R?

a) is.character()

b) is.logical()

c) is.numeric()

d) is.double()

Answer:

c) is.numeric()

Explanation:

The is.numeric() function returns TRUE if the variable is numeric, otherwise FALSE.

10. What is the maximum length of a variable name in R?

a) 256 characters

b) 64 characters

c) No specific limit

d) 128 characters

Answer:

c) No specific limit

Explanation:

R does not impose a specific limit on the length of variable names, but they must be syntactically valid.

Conclusion

These questions help you understand the fundamentals of variables in R, including variable assignment, types, and common operations. Mastering these basics is crucial as variables are the foundation for any R script or analysis. Keep practicing and exploring more complex functions as you grow your R programming skills.