Build Decision Trees from Scratch

Grow classification and regression trees by hand.

Build decision trees from an empty file: Gini impurity, best-split search, greedy recursion, pruning, and sum-of-squared-residuals for regression. Every formula is traced by hand on a toy dataset before it becomes working Python.

beginnermldecision-treesfrom-scratch

23 capsules85 figures~5 hoursby Dr. Raj Dandekar

Read on your Kindle or e-reader

Download the EPUB and read offline — perfect for the train. Works on Kindle, Kobo, Apple Books & more.

Send to Kindle →

00Foundations4 capsules

Foundations — 4 chapters.

01Why Decision Trees?intuitionfree13 min 02The Anatomy of a Decision Treeconceptfree11 min 03Classification vs Regression Treesconcept🔒13 min 04The Toy Dataset We Will Split by Handconcept🔒11 min

01Classification Trees9 capsules

Classification Trees — 9 chapters.

05Starting to Build a Classification Treeconcept🔒11 min 06What is Gini Impurity?math🔒10 min 07Gini Impurity: A Worked Examplemath🔒12 min 08Gini Impurity for Numerical Featuresmath🔒11 min 09Choosing the Best Splitintuition🔒12 min 10Recursion and Stopping Rulesconcept🔒13 min 11Finishing the Classification Treeconcept🔒11 min 12Pruning to Fight Overfittingdeep-dive🔒12 min 13Code an Entire Classification Tree in Pythoncode🔒13 min

02Regression Trees7 capsules

Regression Trees — 7 chapters.

14What are Regression Trees?concept🔒13 min 15Variance and SSR as the Split Criterionmath🔒11 min 16Building the First Regression Splitintuition🔒12 min 17Finishing the Regression Treeconcept🔒15 min 18Regression Trees with Multiple Featuresdeep-dive🔒13 min 19Code an Entire Regression Tree in Pythoncode🔒13 min 20Capstone: Fit and Read a Regression Treeproject🔒10 min

03Wrap-Up and Interview Prep3 capsules

Wrap-Up and Interview Prep — 3 chapters.

21Recap: Two Trees, One Algorithmintuition🔒12 min 22Interview Prep: Decision Treesconcept🔒10 min 23From One Tree to Forests and Boostingdeep-dive🔒11 min

Ratings & reviews

1,357 readers

4.9

499 ratings

5 ★61%

4 ★24%

3 ★8%

2 ★4%

1 ★3%

Rate this book

Ananya Iyer

4 days ago

Beautifully produced and genuinely deep. The reader experience makes it easy to keep going for hours.

Lucia Rossi

2 months ago

Rare mix of depth and readability. The worked examples are the clearest I have seen on this subject.

Aarav Mehta

6 months ago

I read the free preview on a whim and ended up finishing the whole thing in two sittings. Superb pacing.

Priya Nair

9 months ago

Dense but never confusing. Every chapter builds cleanly on the last — you can feel the care in the structure.