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

Modern Tidyverse Patterns

Best practices for modern tidyverse development with dplyr 1.1+ and R 4.3+

Core Principles

1. Use modern tidyverse patterns - Prioritize dplyr 1.1+ features, native pipe, and current APIs
2. Profile before optimizing - Use profvis and bench to identify real bottlenecks
3. Write readable code first - Optimize only when necessary and after profiling
4. Follow tidyverse style guide - Consistent naming, spacing, and structure

Pipe Usage (|> not %>%)

• Always use native pipe |> instead of magrittr %>%
• R 4.3+ provides all needed features

# Good - Modern native pipe
data |>
  filter(year >= 2020) |>
  summarise(mean_value = mean(value))

# Avoid - Legacy magrittr pipe
data %>%
  filter(year >= 2020) %>%
  summarise(mean_value = mean(value))

Join Syntax (dplyr 1.1+)

• Use join_by() instead of character vectors for joins
• Support for inequality, rolling, and overlap joins

# Good - Modern join syntax
transactions |>
  inner_join(companies, by = join_by(company == id))

# Good - Inequality joins
transactions |>
  inner_join(companies, join_by(company == id, year >= since))

# Good - Rolling joins (closest match)
transactions |>
  inner_join(companies, join_by(company == id, closest(year >= since)))

# Avoid - Old character vector syntax
transactions |>
  inner_join(companies, by = c("company" = "id"))

Join Quality Control

• Declare cardinality with relationship to validate join assumptions
• Use unmatched = "error" to catch unexpected non-matches
• Use na_matches = "never" to prevent silent NA joins
• Use tidylog:: prefix interactively to verify join results

# Validate 1:1 relationship — errors if violated
inner_join(x, y, by = join_by(id),
  relationship = "one-to-one")

# Validate many-to-one (left has duplicates, right does not)
left_join(transactions, companies, by = join_by(company == id),
  relationship = "many-to-one")

# Ensure all rows from left match something in right
inner_join(x, y, by = join_by(id),
  unmatched = "error")

# Prevent NA values from matching each other silently
left_join(x, y, by = join_by(id),
  na_matches = "never")

# Combine for strict joins
inner_join(x, y, by = join_by(id),
  relationship = "one-to-one",
  unmatched = "error",
  na_matches = "never")

# Interactive verification with tidylog
# tidylog prints a summary of rows matched/dropped
tidylog::inner_join(x, y, by = join_by(id))