Split

split, join, and map

Learn Perl's core list-transformation trio: split to break strings into lists, join to reassemble them, and map to transform every element.

Train/Test Split and Cross-Validation

Understand how holding out data and using k-fold cross-validation give an honest estimate of how a model will perform on unseen data.

Scikit-learn Cheat Sheet

Core scikit-learn workflow covering train/test splitting, pipelines, preprocessing, common estimators, cross-validation, hyperparameter tuning, and evaluation…