The “map2” Function in R

• Package: purrr

• Purpose: Apply a function to corresponding elements of two lists or vectors and return a list of the results.

• General class: Function

• Required argument(s):

• .x: The first list or vector.

• .y: The second list or vector.

• .f: A function to apply to pairs of elements from .x and .y.

• Notable optional arguments:

• .progress: A logical or function to show progress, useful for long computations.

• Example:

• # Load the required library

  library(purrr)

  # Define two lists of numeric vectors

  list_a <- list(c(1, 2, 3), c(4, 5, 6), c(7, 8, 9))

  list_b <- list(c(10, 20, 30), c(40, 50, 60), c(70, 80, 90))

  # Define a function to add corresponding elements

  add_elements <- function(x, y) {x + y}

  # Apply the function to pairs of vectors from the lists

  results <- map2(list_a, list_b, add_elements)

  # Print the results

  print(results)

• In this example, map2 from the purrr package is used to apply add_elements to pairs of vectors from list_a and list_b. The add_elements function adds corresponding elements from each pair of vectors. The result is a list of vectors, where each vector contains the sums of corresponding elements from the input lists.