Comments and Code Style

A comment is a note for humans; R ignores everything after a # on a line.

# Load the survey results
tax_rate <- 0.2  # UK standard rate

RStudio comments or uncomments selected lines with Ctrl + Shift + C.

What to comment

Clear names explain what code does. Comments are for why:

# Bad: repeats the code
x <- x * 1.2  # multiply x by 1.2

# Good: explains a decision
# Responses before March used a 1-5 scale; rescale to 1-10 to match.
early$score <- early$score * 2

Script sections

In RStudio, a comment ending in four or more dashes creates a section you can jump to and fold:

# Load data ----
# Clean data ----
# Analysis ----

Style in brief

The widely followed tidyverse style guide recommends:

• snake_case names: mean_height, not meanHeight or mean.height.
• <- for assignment.
• Spaces around operators (x <- y + 1) and after commas.
• Two-space indentation.
• Lines under about 80 characters.

The styler package reformats code to this style automatically, and the lintr package flags style issues and likely mistakes.

What's next

You now know enough R to analyze real data. Try the Beginner Projects, then continue to Level 2 — Intermediate, which starts with importing data.