
library(testthat)

source("user_code.R")
test_that("adds a column named category to the returned data frame", {
  df <- data.frame(id = 1:2, value = c(5, 15))
  result <- apply_conditional_transformation(df)
  expect_true("category" %in% names(result),
              info = "The returned data frame should have a column named 'category'.")
})

test_that("assigns 'high' to category where value > 10", {
  df <- data.frame(id = 1:3, value = c(11, 20, 10))
  result <- apply_conditional_transformation(df)
  expect_equal(result$category[1], "high",
               info = "Row 1: Value > 10 should result in 'high' category.")
  expect_equal(result$category[2], "high",
               info = "Row 2: Value > 10 should result in 'high' category.")
})

test_that("assigns 'low' to category where value <= 10", {
  df <- data.frame(id = 1:3, value = c(5, 10, 0))
  result <- apply_conditional_transformation(df)
  expect_equal(result$category[1], "low",
               info = "Row 1: Value <= 10 should result in 'low' category.")
  expect_equal(result$category[2], "low",
               info = "Row 2: Value <= 10 should result in 'low' category.")
  expect_equal(result$category[3], "low",
               info = "Row 3: Value <= 10 should result in 'low' category.")
})

test_that("returns a data frame with the same number of rows as input", {
  df <- data.frame(id = 1:5, value = c(1, 2, 3, 4, 5))
  result <- apply_conditional_transformation(df)
  expect_equal(nrow(result), nrow(df),
               info = "Returned data frame should have the same number of rows as input.")
})

test_main.R

Master the essential R data structures used in exploratory data analysis (EDA), focusing on practical applications and hands-on challenges. This course is designed for learners already familiar with R syntax, core data structures, and data cleaning/wrangling techniques.

Explore the essential R data structures that power effective exploratory data analysis, with a focus on practical usage and hands-on challenges.

Challenge: Conditional Transformations

Solution