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Data Analytics

32 articles tagged #Data Analytics

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Tableau LOD Expressions Returning Unexpected Values: Causes and Fixes

LOD expressions are supposed to give you precise control over aggregation granularity in Tableau β€” but when they return wrong numbers, diagnosing the cause is maddening. Here's a practical breakdown of every common failure mode and how to fix each one.

Jun 19, 2026 10m read πŸ‘ 27

Why Your Pandas groupby Aggregation Is Returning Wrong Numbers

Your groupby().sum() looks right but the numbers are off. Before you blame the data, check these common Pandas aggregation traps β€” duplicate rows, NaN handling, dtype coercion, and more β€” that silently corrupt your results.

Jun 19, 2026 9m read πŸ‘ 37

Fixing Excel SUMIF That Returns Zero When Criteria Look Correct

Your SUMIF formula looks perfect but keeps returning zero. The data is right there. This guide walks through every real cause β€” from invisible spaces to number-stored-as-text β€” and shows you exactly how to fix each one.

Jun 15, 2026 8m read πŸ‘ 76

Debugging Silent Row Loss in a Pandas merge() Left Join

You ran a left join in Pandas and expected to keep every row from the left DataFrame β€” but some rows vanished without a warning. Here's how to track down exactly why and fix it for good.

Jun 15, 2026 8m read πŸ‘ 37
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