
library(testthat)

source("user_code.R")
test_that("student list structure is correct", {
    expect_true(exists("student"), info = "student list does not exist")
    expect_true(is.list(student), info = "student is not a list")
    expect_true("name" %in% names(student), info = "student list missing 'name'")
    expect_true("age" %in% names(student), info = "student list missing 'age'")
    expect_true("courses" %in% names(student), info = "student list missing 'courses'")
    expect_true(is.list(student$courses), info = "student$courses is not a list")
    expect_true(all(c("Math", "History", "Biology") %in% names(student$courses)), info = "courses list missing at least one required course")
    expect_equal(student$name, "Alex Smith", info = "student name is not 'Alex Smith'")
    expect_equal(student$age, 20, info = "student age is not 20")
    expect_equal(student$courses$Math, 88, info = "Math grade is not 88")
    expect_equal(student$courses$History, 92, info = "History grade is not 92")
    expect_equal(student$courses$Biology, 85, info = "Biology grade is not 85")
})

test_that("math_grade variable is correct and printed", {
    expect_true(exists("math_grade"), info = "math_grade variable does not exist")
    expect_equal(math_grade, 88, info = "math_grade does not equal 88")
    out_user_code <- capture.output(print(math_grade))
    expect_true(any(grepl("88", out_user_code)), info = "math_grade value was not printed correctly")
})

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: Work with Named and Nested Lists

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