The “pivot_longer” Function in R

• Package: tidyr

• Purpose: To pivot data from wide to long format by gathering multiple columns into key-value pairs.

• General Class: Data Reshaping

• Required Argument(s):

• data: The data frame to reshape.

• cols: Columns to pivot into longer format.

• Notable Optional Arguments:

• names_to: The name of the new column that will store the names of the pivoted columns.

• values_to: The name of the new column that will store the values of the pivoted columns.

• names_prefix: Prefix to apply to the names of the original columns. The default is NULL.

• Example (with Explanation):

• # Load necessary packages
  library(tidyr)
  
  # Create a sample data frame
  data <- data.frame(
  ID = 1:3,
  Apple_2021 = c(10, 15, 20),
  Orange_2021 = c(25, 30, 35),
  Apple_2022 = c(40, 45, 50),
  Orange_2022 = c(55, 60, 65)
  )
  
  # Pivot the data from wide to long format
  result <- pivot_longer(data, cols = -ID, names_to = "Fruit_Year", values_to = "Value")
  
  # Display the result
  print(result)

• In this example, the pivot_longer function from the tidyr package is used to reshape the sample data frame data from wide to long format. The columns ‘Apple_2021’, ‘Orange_2021’, ‘Apple_2022’, and ‘Orange_2022’ are gathered into key-value pairs, with the names stored in a new column ‘Fruit_Year’ and the values stored in a new column ‘Value’. The result is a new data frame result containing the reshaped data.