The “do” Function in R

• Package: dplyr

• Purpose: To apply a custom function to each group in a grouped data frame and return the results as a new data frame.

• General Class: Data Manipulation

• Required Argument(s):

• data: The grouped data frame.

• fun: A function to apply to each group.

• Notable Optional Arguments:

• None.

• Example (with Explanation):

• # Load necessary packages
  library(dplyr)
  
  # Create a sample data frame
  data <- data.frame(
  group = c("A", "A", "B", "B"),
  value = c(10, 15, 20, 25)
  )
  
  # Group the data frame by 'group' column and apply custom function to each group
  result <- data %>%
  group_by(group) %>%
  do(mean_value = mean(.$value)) %>%
  data.frame()
  
  # Display the result
  print(result)

• In this example, the do function from the dplyr package is used to calculate the mean value of the ‘value’ column for each group defined by the ‘group’ column in the sample data frame data. The mean function is applied to each group using the do function, and the result is stored in a new data frame with a column named ‘mean_value’ containing the mean value for each group.