📎 This article includes 2 downloadable practice files ↓
📘 R Beginner Course · Lesson 3 of 6
“`r
read_csv shows the type it guessed for each column; fix wrong guesses with col_types. Missing values are NA; most functions need na.rm = TRUE to ignore them (e.g. mean(x, na.rm = TRUE)).
💡 For dd-mm-yyyy dates use lubridate::dmy(); for yyyy-mm-dd use ymd().
Code for this course follows standard, current syntax; we test JavaScript and PowerShell scripts before publishing, and R/Java/Rust examples are kept to core language features. Tell us if anything fails on your setup.
Practice
Read sales.csv and check its structure.
← R Lesson 2: Vectors and Data Frames R Lesson 4: dplyr — filter, mutate, summarise → 📎 Practice files for this article Free to use for learning. Files with macros (.bas) are plain text — import them with Alt +F11 → File → Import File, and always test on a copy.
Written by Atul Vij Atul (AJ) builds office-automation and local-first AI tools as Atulya AI, and works with Excel, SAP and Oracle EPM every day. He writes about the shortcuts, macros and automations that actually save time — plus the occasional wacky fact. Videos on YouTube: Lazy Automator AI (@LazyAutomatorAI).
More posts by Atul → ← Previous R Lesson 2: Vectors and Data FramesNext → R Lesson 4: dplyr — filter, mutate, summarise✨ Ask AI about this article Stuck on a step? Ask a question and the AI answers using this article.
Your question about this article Model Auto — best model for the task GPT-OSS 120B — OpenAI · strongest reasoning · counts as 2 DeepSeek R1 — DeepSeek · thinks step by step (slow) · counts as 2 Llama 3.3 70B — Meta · fast, all-round Qwen 2.5 Coder 32B — Alibaba · best for code Gemma 4 26B — Google · clear explanations Mistral Small 3.1 — Mistral · quick GPT-OSS 20B — OpenAI · balanced Llama 4 Scout — Meta · newest Llama Gemma Sea Lion V4 27b — Aisingapore Glm 4.7 Flash — Zai-org Llama 3.1 8b — Meta Llama 3.2 3b — Meta Nemotron 3 120b A12b — Nvidia · counts as 2 Qwen3 30b A3b — Qwen Qwen3.8 27b — Qwen Qwq 32b — Qwen · counts as 2 Free · AI can be wrong Ask ✨
