R Programming Language Certification Technology & Digital Applications 5

Question 1

In R, what is the `reticulate` package used for?

Accepted Answer

Running Python code and sharing objects between R and Python

Answer

The reticulate package provides a comprehensive interface between R and Python, allowing R users to call Python functions, import modules, and share data between sessions.

Question 2

Which R function is used to apply a function over the rows or columns of a matrix, specified by the MARGIN argument?

Accepted Answer

apply()

Answer

`apply()` iterates over rows (MARGIN=1) or columns (MARGIN=2) of a matrix or array and applies a specified function, returning a vector or matrix of results.

Question 3

What is the purpose of `withr::with_dir()` in R testing and scripting contexts?

Accepted Answer

Temporarily changes the working directory for the duration of a code block

Answer

`withr::with_dir()` temporarily changes the working directory for the duration of the expression and restores the original directory when done, even if an error occurs.

Question 4

In R, which package provides the `datatable()` function to render interactive, searchable HTML tables in R Markdown or Shiny?

Accepted Answer

DT

Answer

The DT package wraps the JavaScript DataTables library, providing `datatable()` to create interactive HTML tables with sorting, filtering, and pagination.

Question 5

Which R function retrieves the current system time as a POSIXct object?

Accepted Answer

Sys.time()

Answer

`Sys.time()` returns the current date and time as a POSIXct object, suitable for time-stamping operations or calculating elapsed time.

R Programming Language Certification Practice Test

R Programming Language Certification Practice Test

R Programming Language Certification Technology & Digital Applications 5