Introduction to R—IND215

A curated set of R materials for analytics students

Welcome to IND215

This interactive website provides a comprehensive four-part introduction to R programming specifically designed for students in analytics curricula. The course emphasizes R’s language fundamentals, the tidyverse ecosystem, and data manipulation for statistical computing and data science.

Why R for Analytics?

R has been the gold standard for statistical computing and data analysis for good reasons:

🌟 Statistical Foundation

  • Created by statisticians for statistical analysis
  • Standard tool in academia, research, and data science
  • Preferred language for statistical modeling and hypothesis testing

💪 Rich Ecosystem

  • Comprehensive statistical libraries (stats, MASS)
  • Elegant data manipulation (tidyverse: dplyr, tidyr, ggplot2)
  • Advanced visualization capabilities (ggplot2, plotly, shiny)
  • Machine learning and predictive modeling (caret, randomForest)

🎯 Data-First Design

  • Built-in support for statistical data types (factors, time series)
  • Vectorized operations for efficient data processing
  • Seamless integration with databases and file formats
  • Interactive data exploration and analysis
  • Publication-ready graphics and reports

The R Learning Journey: A Humorous Reality Check

Learning R is an adventure filled with “aha!” moments, head-scratching confusion, and the occasional existential crisis about why your data frame suddenly became a factor (again). Every R programmer has traveled this path, from their first 2 + 2 to their thousandth Google search about why their ggplot won’t cooperate.

Below is a humorous, fictitious R function that captures the universal experiences every R learner encounters. As you progress through this course, you’ll gradually understand why each of these moments is both frustrating and funny. Consider it a preview of coming attractions – if you don’t find it amusing now, bookmark it and return after a few weeks of R. You’ll be laughing (or crying) in recognition!

The Universal R Learning Timeline

This function documents real phenomena you’ll encounter: - Days 1-10: The honeymoon phase where everything seems logical until you meet factors - Days 10-100: The valley of despair where you discover R’s “quirks” - Days 100-365: The plateau of productivity where you can actually wrangle data (while still Googling constantly) - Days 365+: The eternal journey where you realize the tidyverse keeps evolving

r_newbie_experience <- function(day) {
  # Simulates the emotional journey of learning R.
  # Warning: Results may vary. Side effects include: false confidence,
  # existential dread about factors, sudden urges to pipe everything,
  # and an unhealthy relationship with Stack Overflow.
  #
  # Note: This function is 100% accurate based on extensive field research
  # (aka crying over RStudio worldwide).

  experiences <- list(
    `1` = "2 + 2  # I AM A DATA SCIENTIST NOW!!!",
    `2` = "x <- 'R is easy'  # This arrow thing is cool!",
    `3` = "c(1, 2, 3)  # Everything is a vector? Even single numbers?!",
    `4` = "data.frame(x = 1:3, y = 4:6)  # Look at me making data!",
    `5` = "my_data$new_column <- 'value'  # Dollar signs everywhere!",
    `6` = "factor(c('A', 'B', 'A'))  # Why are my letters ordered weird?",
    `7` = "mean(c(1, 2, NA))  # Returns NA. R is broken.",
    `8` = "mean(c(1, 2, NA), na.rm = TRUE)  # Oh... that's embarrassing",
    `9` = "library(tidyverse)  # Installed 47 packages. Is this normal?",
    `10` = "data %>% filter()  # What is this pipe thing?",
    `12` = "ggplot(data, aes(x, y)) + geom_point()  # I made a chart!",
    `14` = "install.packages('everything')  # Package not found. Dreams crushed.",
    `15` = "subset(data, condition)  # Why does everyone say this is bad?",
    `18` = "data %>% select(everything())  # Pipe addiction begins",
    `20` = "for(i in 1:10) print(i)  # Loops work but everyone judges me",
    `25` = "apply(matrix, 1, function(x) sum(x))  # Functions have functions?",
    `30` = "str(object)  # Everything has structure. Mind = blown",
    `35` = "read.csv('file.csv')  # Why are my numbers now factors?!",
    `40` = "stringsAsFactors = FALSE  # The magic incantation",
    `45` = "data$column[data$other_column == 'value']  # Bracket hell",
    `50` = "library(dplyr); data %>% filter(column == 'value')  # Enlightenment",
    `55` = "Error: object 'column' not found  # But I can see it right there!",
    `60` = "data %>% mutate(new = old * 2)  # Mutate sounds violent",
    `65` = "group_by(category) %>% summarise(mean = mean(value))  # I'm a wizard!",
    `70` = "left_join(df1, df2, by = 'id')  # Joins without SQL?",
    `75` = "pivot_longer(data, cols = everything())  # Reshape magic",
    `80` = "ggplot() + theme_minimal() + labs() + scale_x_continuous()  # Layered grammar",
    `85` = "ggsave('plot.png', width = 8, height = 6, dpi = 300)  # Publication ready!",
    `90` = "map(list, ~function(.x))  # Functional programming in R?",
    `95` = "case_when(condition1 ~ result1, TRUE ~ default)  # Vectorized if-else",
    `100` = "data[data$x > 5 & data$y < 10, ]  # Back to base R. Feeling dirty.",
    `110` = "glue('Hello {name}!')  # String interpolation discovered",
    `120` = "# Started answering R questions (incorrectly) on Stack Overflow",
    `130` = "options(stringsAsFactors = FALSE)  # Set global defaults",
    `140` = "library(here); here('data', 'file.csv')  # Path management zen",
    `150` = "renv::init()  # Environment management. Finally!",
    `180` = "Discovered R Markdown. Rewrote everything. Literate programming!",
    `200` = "shiny::fluidPage()  # Interactive web apps in R?!",
    `250` = "data.table vs dplyr debates. Chose sides. Lost friends.",
    `300` = "Rcpp::cppFunction()  # C++ in R. Peak performance.",
    `365` = "# Still googling 'how to exit vim' but my R analysis is solid",
    `400` = "targets::tar_make()  # Pipeline management. Professional level.",
    `500` = "Writing R packages. DESCRIPTION file mysteries solved.",
    `600` = "CRAN submission. Peer review trauma begins.",
    `700` = "Dreams in dplyr. Nightmares about factors.",
    `800` = "Discovered {{}}.  Tidy evaluation everywhere.",
    `900` = "10 years later: Still finding new CRAN packages daily",
    `1000` = "Achieved enlightenment: Everything is a list (even data frames)"
  )

  # Special milestone messages
  if (day < 0) {
    return("Error: Time travel not yet implemented in R 4.x (check CRAN)")
  } else if (day == 0) {
    return("Day 0: Googling 'R vs Excel' (preparing for enlightenment)")
  } else if (day == 42) {
    return("Day 42: The answer to life, universe, and missing values")
  } else if (day == 404) {
    return("Day 404: Object not found. Try ls() again later.")
  } else if (day == 418) {
    return("Day 418: I'm a teapot. Also, discovered Easter eggs in R")
  } else if (day == 314) {
    return(paste0("Day ", day, ": pi  # Built-in constant. Math rocks!"))
  } else if (as.character(day) %in% names(experiences)) {
    return(experiences[[as.character(day)]])
  } else if (day > 1000) {
    return(paste0("Day ", day, ": Realized the real R was the data we wrangled along the way"))
  } else if (day > 365) {
    return(paste0("Day ", day, ": Still discovering that everything is a vector (even confusion)"))
  } else {
    states <- c(
      "Alternating between 'I'm a data wizard' and 'I know nothing'",
      "Debugging code that worked yesterday without changes",
      "Adding print() statements everywhere like breadcrumbs",
      "Copy-pasting from Stack Overflow with pride",
      "Explaining to rubber duck why dplyr should work",
      "Discovering the bug was a missing comma. Again.",
      "Refactoring working code because 'tidyverse is cleaner'",
      "Breaking production on a Friday at 4:59 PM"
    )
    return(paste0("Day ", day, ": ", sample(states, 1)))
  }
}

# Test the journey with milestone days
cat("=== The R Newbie Journey: Extended Director's Cut ===\n\n")
test_days <- c(0, 1, 4, 9, 30, 42, 60, 100, 365, 404, 418, 500, 1000)
for (day in test_days) {
  cat(sprintf("Day %4d: %s\n", day, r_newbie_experience(day)))
}

Ready to Begin?

Start your R journey by:

  1. 📚 Reading the Course Syllabus
  2. 📅 Reviewing the Course Schedule
  3. 💻 Setting up R and RStudio with our Getting Started Guide