Here are top R language interview questions,
1. What is R programming language?
R is a
programming language and environment specifically designed for data analysis
and statistical computing.
2. How do you install and load a
package in R?
You can
install a package using the `install.packages("package_name")`
function and load it using `library(package_name)`.
3. Explain what data frames are in
R.
Data frames
are a two-dimensional tabular data structure in R, similar to a spreadsheet or
SQL table. They store data in rows and columns, where each column can have a
different data type.
4. How do you create a sequence of
numbers in R?
You can
create a sequence using the `seq()` function. For example, `seq(1, 10)`
generates a sequence from 1 to 10.
5. What is the use of the `attach()`
function in R?
The
`attach()` function is used to make data frames or lists available by name
directly. However, it is not recommended to use `attach()` due to potential
conflicts and bugs.
6. Explain the difference between
`==` and `=` in R.
- `==`: It
is used for equality comparison (e.g., `a == b` checks if `a` is equal to `b`).
- `=`: It
is used for variable assignment (e.g., `x = 5` assigns the value 5 to the
variable `x`).
7. What is the purpose of the
`subset()` function in R?
The
`subset()` function is used to extract a subset of a data frame based on
specified conditions.
8. How do you handle missing or NaN
values in R?
You can use
functions like `is.na()`, `complete.cases()`, and `na.omit()` to identify and
handle missing or NaN values in R.
9. Explain what the `%>%`
operator (pipe operator) does in R.
The
`%>%` operator, known as the pipe operator, is used with the `magrittr`
package to chain multiple operations together in a readable way. It takes the
output of one function and passes it as the first argument to the next
function.
10. What are factors in R?
Factors are
used to represent categorical data in R. They are useful for storing and
handling data with distinct categories or levels.
11. How do you plot a histogram in
R?
You can
plot a histogram using the `hist()` function. For example:
```R
data <-
c(10, 20, 30, 40, 50)
hist(data)
```
12. Explain the purpose of the
`aggregate()` function in R.
The
`aggregate()` function is used for data aggregation based on specified
conditions, such as calculating summary statistics for subsets of data.
13. What are the main data
structures in R?
The main
data structures in R include vectors, matrices, data frames, and lists.
14. How do you read data from a CSV
file into R?
You can
read data from a CSV file using the `read.csv()` function. For example:
```R
data <-
read.csv("file.csv")
```
15. What is the purpose of the
`apply()` function in R?
The
`apply()` function is used to apply a function to the rows or columns of a
matrix or data frame.
16. Explain the use of the `dplyr`
package in R.
The `dplyr`
package is used for data manipulation and provides functions like `filter()`,
`select()`, `mutate()`, `group_by()`, and `summarize()` to efficiently work
with data frames.
17. How do you merge two data frames
in R?
You can use
functions like `merge()` or `rbind()` to merge two data frames based on common
columns or bind them row-wise, respectively.
18. What is the purpose of the
`rep()` function in R?
The `rep()`
function is used to replicate elements, creating vectors of repeated values.
19. How do you create a scatter plot
in R?
You can
create a scatter plot using the `plot()` function and specifying the type as
"p" (for points). For example:
```R
x <-
c(1, 2, 3, 4, 5)
y <-
c(10, 15, 20, 25, 30)
plot(x, y,
type = "p")
```
20. Explain what the `set.seed()`
function is used for in R.
The
`set.seed()` function is used to set a random seed in R. It ensures
reproducibility when working with random number generation, making results
consistent across different runs.
Above are few top R language interview questions. Remember to prepare and expand on these answers.
Good luck with your interview! 👍
0 Comments
Please share your comments ! Thank you !