Python · SQL · Excel · ML · AI
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Step-by-step tutorials with tested code, clear explanations and the common mistakes nobody warns you about. Written in plain English for beginners and improving analysts.
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Five focused tracks, each built from practical tutorials you can follow on your own machine.
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New to data? Follow this path
Work through these six tutorials in order and you will be able to load, clean, summarise and query real data – and understand the first idea behind machine learning.
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Latest tutorials
Fresh guides, newest first.
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Classification Metrics Explained: Accuracy, Precision, Recall, F1
Precision and recall explained with Python: confusion matrix, accuracy, F1, decision thresholds, ROC AUC and how to choose the right metric.
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Merging and Joining DataFrames in Pandas
Learn to merge and join DataFrames in pandas: inner, left, outer joins, merge keys, validate, indicator and how to avoid duplicated rows.
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Linear Regression in Python with scikit-learn
Build linear regression in Python with scikit-learn: training, MAE/RMSE/R², baselines, coefficients, residual checks and categorical features.
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Excel Pivot Tables: From Raw Data to Summary in Minutes
A practical guide to Excel pivot tables: preparing data, rows/columns/values, grouping dates, percentages, slicers, refreshing and common mistakes.
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SQL GROUP BY and HAVING: Summarising Data Properly
Learn SQL GROUP BY and HAVING: aggregate functions, NULL behaviour, grouping by month, COUNT DISTINCT, conditional aggregation and percentages.
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How to Use ChatGPT for Data Analysis (Safely and Effectively)
A safe, practical workflow for using ChatGPT and other AI assistants for data analysis: privacy, prompts, generating code and verifying results.
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Train/Test Split Explained (and Why It Matters)
Understand the train/test split in machine learning: scikit-learn code, stratify, validation sets, time-series and group splits, and avoiding data leakage.
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XLOOKUP in Excel: The Complete Beginner’s Guide
Learn XLOOKUP in Excel step by step: exact and approximate matches, not-found messages, looking left, wildcards, last match and two-way lookups.
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SQL Joins Explained: INNER, LEFT, and the Mistakes Everyone Makes
SQL joins explained with runnable examples: INNER, LEFT, FULL, self joins, anti-joins, ON vs WHERE and the fan-out trap that inflates totals.
Hi, I’m Lucky Joseph
I’m a UK-based writer with a data science background. DataScienceWay is where I publish practical, tested tutorials on the tools people actually use with data – explained honestly, including the parts that usually go wrong.
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