
library(testthat)

source("user_code.R")
test_that("survey_response is a list with required fields and types", {
  expect_true(exists("survey_response"), info = "survey_response variable must exist")
  expect_true(is.list(survey_response), info = "survey_response must be a list")
  expect_true("age" %in% names(survey_response), info = "survey_response must have an 'age' field")
  expect_true(is.numeric(survey_response$age), info = "'age' must be numeric")
  expect_true("gender" %in% names(survey_response), info = "survey_response must have a 'gender' field")
  expect_true(is.character(survey_response$gender), info = "'gender' must be character")
  expect_true("consent" %in% names(survey_response), info = "survey_response must have a 'consent' field")
  expect_true(is.logical(survey_response$consent), info = "'consent' must be logical")
  expect_true("comment" %in% names(survey_response), info = "survey_response must have a 'comment' field")
  expect_true(is.null(survey_response$comment), info = "'comment' must be NULL (missing field)")
})

test_that("student_grades is a data frame with correct structure", {
  expect_true(exists("student_grades"), info = "student_grades variable must exist")
  expect_true(is.data.frame(student_grades), info = "student_grades must be a data frame")
  expect_true(nrow(student_grades) >= 2, info = "student_grades must have at least two rows")
  expect_true(all(c("name", "id", "assignment1", "assignment2") %in% colnames(student_grades)),
              info = "student_grades must have columns: name, id, assignment1, assignment2")
  expect_true(is.character(student_grades$name), info = "'name' column must be character")
  expect_true(is.numeric(student_grades$id), info = "'id' column must be numeric")
  expect_true(is.numeric(student_grades$assignment1), info = "'assignment1' column must be numeric")
  expect_true(is.numeric(student_grades$assignment2), info = "'assignment2' column must be numeric")
})

test_that("mixed_record is a list with correct components", {
  expect_true(exists("mixed_record"), info = "mixed_record variable must exist")
  expect_true(is.list(mixed_record), info = "mixed_record must be a list")
  expect_true("scores" %in% names(mixed_record), info = "mixed_record must have 'scores' field")
  expect_true(is.numeric(mixed_record$scores), info = "'scores' must be a numeric vector")
  expect_true("label" %in% names(mixed_record), info = "mixed_record must have 'label' field")
  expect_true(is.character(mixed_record$label), info = "'label' must be character")
  expect_true("passed" %in% names(mixed_record), info = "mixed_record must have 'passed' field")
  expect_true(is.logical(mixed_record$passed), info = "'passed' must be logical")
})

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: Choose the Right Structure

解答