
library(testthat)

source("user_code.R")
test_that("satisfaction_factor is a factor", {
  expect_true(exists("satisfaction_factor"), info = "The variable 'satisfaction_factor' does not exist.")
  expect_true(is.factor(satisfaction_factor), info = "'satisfaction_factor' is not a factor.")
})

test_that("satisfaction_factor has correct levels and order", {
  expect_true(all(levels(satisfaction_factor) == c("Dissatisfied", "Neutral", "Satisfied")), 
              info = "Levels are not set as 'Dissatisfied', 'Neutral', 'Satisfied' in that order.")
})

test_that("satisfaction_factor is ordered", {
  expect_true(is.ordered(satisfaction_factor), info = "'satisfaction_factor' is not an ordered factor.")
})

test_that("structure_info contains structure output", {
  expect_true(exists("structure_info"), info = "The variable 'structure_info' does not exist.")
})

test_main.R

Master the essential data structures in R, including lists, data frames, and factors. Learn how to create, manipulate, and analyze data using R's powerful tools, with engaging explanations and real-world challenges designed for beginners.

Explore the fundamentals of lists in R, including how to create, access, and manipulate both simple and nested lists. Learn the differences between lists and data frames, and discover practical uses for each.

Master the creation and manipulation of data frames in R, including adding, removing, and modifying columns and rows, as well as filtering and sorting data for analysis.

Discover how to use factors in R to handle categorical data, including setting levels, ordering, and avoiding common mistakes.

Challenge: Create and Use Factors

解答