claude-code-r-skills: Skill for Claude Code

R Style Guide & Function Writing Best Practices

Consistent naming, spacing, structure, and function design for R code

Function Writing Best Practices

Structure and Style

# Good function structure
rescale01 <- function(x) {
  rng <- range(x, na.rm = TRUE, finite = TRUE)
  (x - rng[1]) / (rng[2] - rng[1])
}

# Use type-stable outputs
map_dbl()   # returns numeric vector
map_chr()   # returns character vector
map_lgl()   # returns logical vector

Naming and Arguments

# Good naming: snake_case for variables/functions
calculate_mean_score <- function(data, score_col) {
  # Function body
}

# Prefix non-standard arguments with .
my_function <- function(.data, ...) {
  # Reduces argument conflicts
}

Style Guide Essentials

Object Names

• Use snake_case for all names
• Variable names = nouns, function names = verbs
• Avoid dots except for S3 methods

# Good
day_one
calculate_mean
user_data

# Avoid
DayOne
calculate.mean
userData

Spacing and Layout

# Good spacing
x[, 1]
mean(x, na.rm = TRUE)
if (condition) {
  action()
}

# Pipe formatting
data |>
  filter(year >= 2020) |>
  group_by(category) |>
  summarise(
    mean_value = mean(value),
    count = n()
  )

Assignment

# Good - Use <- for assignment
x <- 5

# Avoid - = for assignment (use only for function arguments)
x = 5  # Less clear intent

Indentation and Line Length

• Use 2 spaces for indentation (never tabs)
• Keep lines under 80 characters when possible
• For long function calls, put each argument on its own line

# Good - Long function call
do_something_complicated(
  data = my_data,
  arg_one = value_one,
  arg_two = value_two,
  arg_three = value_three
)

# Good - Long pipe chain
result <- data |>
  filter(year >= 2020) |>
  mutate(
    new_var = old_var * 2,
    another_var = str_to_lower(text_var)
  ) |>
  summarise(
    mean_value = mean(value),
    .by = category
  )

Comments

# Good - Comments explain WHY, not WHAT
# Calculate running average to smooth noise in sensor data
running_avg <- zoo::rollmean(values, k = 5)

# Avoid - Comments that just repeat the code
# Add 1 to x
x <- x + 1