The correct answer is D. all of the mentioned.
dcast, ucast, and rcast are all functions in the tidyverse package that can be used to cast data frames. Casting is the process of converting a data frame from one type to another. For example, you can use dcast to convert a data frame with columns of dates and numbers to a data frame with columns of months and years.
dcast is the most general of the three functions. It can be used to cast data frames to any type of data frame. ucast is a specialized function that can be used to cast data frames to a specific type of data frame, such as a data frame with columns of dates and numbers. rcast is a specialized function that can be used to cast data frames to a specific type of data frame, such as a data frame with columns of months and years.
Here is an example of how to use dcast to cast a data frame to a data frame with columns of months and years:
“`
library(tidyverse)
df <- data.frame(
month = c(“January”, “February”, “March”, “April”, “May”, “June”, “July”, “August”, “September”, “October”, “November”, “December”),
year = c(2022, 2022, 2022, 2022, 2022, 2022, 2022, 2022, 2022, 2022, 2022),
value = c(10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120)
)
dcast(df, month ~ year, value.var = “value”)
“`
This will produce a data frame with columns of months and years, and a column of values for each month and year.