Ruby

Ruby is best known for web development with Rails and rarely shows up in data science, but its blocks and collection methods make numeric code read almost like the formulas: values.sum, labels.tally, and sort_by do a lot of the work. Ruby has no statistics in its standard library, so nothing needs avoiding. The only thing we leave out is the csv library: since Ruby 3.4 it’s a bundled gem, installed alongside Ruby but no longer part of the standard library. The implementations split each line on commas instead.

Quirks

• Integer division truncates: 7 / 2 is 3. Use fdiv or convert to a float first.
• tally counts each distinct value in one call: [1, 2, 2, 3].tally is {1 => 1, 2 => 2, 3 => 1}.
• sort_by isn’t guaranteed to be stable, so code that needs ties in file order adds the position to the sort key.

git clone https://github.com/qnixon/dswithx.git
cd dswithx
python3 harness/run_tests.py --language ruby