Update cars.R

[UniversidadNacionalAsuncion]

Hi @wch,

I added a conversion of the base R cars dataset into SI units and included the conversion script in my repository: https://github.com/UniversidadNacionalAsuncion/Modelos_Lineales_Generalizados/blob/main/Regresi%C3%B3n%20Lineal%20con%20R/mbayru-script.R

Summary of what the script does

• Loads cars from datasets::cars.
• Computes SI columns:
  • speed_ms = speed (mph) × 0.44704 → meters/second
  • dist_m = dist (ft) × 0.3048 → meters
• Rounds converted values to 6 decimal places for reproducible precision.
• Writes out a file mbay_ruguata.R that defines mbay_ruguata <- data.frame(...) with the SI columns.
• Prints usage instructions: source('mbay_ruguata.R').

Why I recommend accepting this change

• Teaching & reproducibility: Many textbooks and courses use SI units. Providing SI columns removes a common friction point for instructors and students, letting them run examples without adding conversion steps.
• Interoperability: SI units make the dataset easier to use across modern workflows (including Python users), reducing unit-related errors and improving cross-language reproducibility.
• Keeps R competitive: Python datasets and libraries often ship with preprocessed, well-documented examples. Small, low-risk improvements like this help keep R’s base datasets immediately useful for contemporary data science workflows.
• Low risk: The change is non-intrusive — it adds new columns rather than overwriting originals, so existing code that expects the original speed and dist is unaffected.

Technical notes / transparency

• Conversion constants used in the script:
  • mph_to_ms <- 0.44704 (1 mph = 0.44704 m/s)
  • ft_to_m <- 0.3048 (1 ft = 0.3048 m)
• The current script generates the object mbay_ruguata and writes only the SI columns into mbay_ruguata.R. If you prefer:
  1. I can modify the script so the generated R file contains the full dataset (original columns + SI columns), or
  2. I can add the SI columns directly into the repo’s data/cars file so the dataset in-place contains both unit systems.
• If you have a preferred naming convention (e.g., speed_m_s / dist_m vs speed_ms / dist_m or speed_si / dist_si), tell me which you prefer and I’ll update the PR accordingly.

Requested action

• Please review the script and the generated data. If acceptable, I’d appreciate merging this change so cars users can immediately work in SI units without extra steps. If you want a different output format or naming convention, I can update the PR right away.

Thanks for maintaining this important resource — small improvements like this have a big impact for teaching and reproducible workflows.

Best,
Derlis Sosa

derlisdev@gmail.com

[gavinsimpson]

@UniversidadNacionalAsuncion You know this is a read only mirror of the R sources? Nothing is going to happen with this PR. You should file a bug on R's bug tracker if you want this looked at.