ML & Data Science
7 results Clear
TutorialData Engineering · ReliabilityYour Retry Worked. That Is How You Got Two Rows.
Retries fix transient failures, but they can also duplicate payments, records, and side effects. Here is how idempotency keys, unique constraints, and atomic writes make retries safe.
Ibrahim Denis Fofanah·Sep 25, 2026·8 min
TutorialSQL · Data QualityYour SQL Query Did Not Fail. NULL Changed the Question.
NULL does not mean zero, blank, or false. It introduces UNKNOWN, and that third truth value can quietly change filters, exclusions, joins, and aggregates.
Ibrahim Denis Fofanah·Sep 25, 2026·10 min
TutorialAnalytics Engineering · Metrics · Semantic LayerYour KPI Needs a Contract: Build Metrics That Survive Dashboards and AI
A metric is more than an aggregation. Define its entity, grain, time, eligibility, joins, tests, and change policy so dashboards and AI return the same answer.
Ibrahim Denis Fofanah·Sep 25, 2026·9 min
TutorialData Engineering · ReliabilityYour Pipeline Passed. Your Dashboard Is Still Wrong.
A green pipeline only proves the code ran. This practical guide shows how contracts, freshness checks, semantic tests, lineage, and safe promotion catch schema drift before it corrupts a dashboard.
Ibrahim Denis Fofanah·Sep 11, 2026·7 min
- TutorialModel Evaluation · Time Series
Your Train-Test Split Is Leaking the Future
A random split can make a forecasting model look excellent by training on records that occur after its test rows. Here is how to build a time-aware evaluation that rehearses production instead of leaking the future.
Ibrahim Denis Fofanah·Sep 7, 2026·10 min
- TutorialData Thinking · Part 3
Before You Clean Your Data, Ask This One Question: Is It Actually Dirty?
A lender's income field was 23% empty, and the gap turned out to be the best feature in the dataset. Three mechanisms behind missing data, four diagnostics that tell them apart, and why cleaning is a provenance problem in disguise.
Ibrahim Denis Fofanah·Jul 28, 2026·12 min
TutorialPython · Data Cleaning7 Pandas One-Liners That Replace 20 Lines of Data Cleaning
Seven vectorized pandas one-liners that replace dozens of lines of manual cleaning code, with copy-paste examples.
Ibrahim Denis Fofanah·Jul 10, 2026·3 min