
library(testthat)

source("user_code.R")
test_that("returns only pairs with age 18 or above", {
  names <- c("Alice", "Bob", "Carol", "Dave")
  ages <- c(17, 22, 15, 30)
  result <- pair_and_filter(names, ages)
  expect_true(is.list(result), info = "Result should be a list")
  expect_equal(length(result), 2, info = "Should return two pairs")
  expect_true(all(sapply(result, function(x) x$age >= 18)), info = "All ages should be 18 or above")
  expect_equal(result[[1]]$name, "Bob", info = "First kept pair should be Bob")
  expect_equal(result[[2]]$name, "Dave", info = "Second kept pair should be Dave")
})

test_that("returns empty list if all ages below 18", {
  names <- c("Eve", "Frank")
  ages <- c(10, 15)
  result <- pair_and_filter(names, ages)
  expect_true(is.list(result), info = "Result should be a list")
  expect_equal(length(result), 0, info = "Should return empty list if all ages are below 18")
})

test_that("returns all pairs if all ages are 18 or above", {
  names <- c("Gina", "Hank")
  ages <- c(18, 25)
  result <- pair_and_filter(names, ages)
  expect_true(is.list(result), info = "Result should be a list")
  expect_equal(length(result), 2, info = "Should return all pairs if all ages are 18 or above")
  expect_equal(result[[1]]$name, "Gina", info = "First pair should be Gina")
  expect_equal(result[[2]]$name, "Hank", info = "Second pair should be Hank")
})

test_main.R

Master the art of writing and using functions in R, from basic syntax to advanced functional programming techniques. This course guides you through creating your own functions, leveraging anonymous functions, and applying functional programming concepts to solve real-world problems in R.

Learn how to define, call, and utilize functions in R, including understanding parameters, return values, and default arguments.

Discover how to use anonymous (inline) functions for concise, on-the-fly operations, and see how they fit into R's functional programming paradigm.

Apply functional programming concepts in R to solve real-world problems, focusing on writing concise, reusable, and efficient code.

Challenge: Functional Data Analysis

Solution