Posts about Data Transformation.
Joining a column of names or tags into one comma-separated string used to need TEXTJOIN or a helper column. REDUCE does it in one formula, and lets you transform each item before it gets concatenated.
Most introductions to star schema start with the diagram. The star, the centre, the spokes. This one starts with the question: what problem does a fact table solve that a flat table doesn't? Part 1 builds the intuition before the vocabulary, so the rest of the series makes immediate sense.
In a small team, you're the analyst, the engineer, the dashboard designer, and the person who explains what a p-value is at the all-hands.
The Keep Rows filter in the Power Query UI handles 80% of row filtering tasks without you ever opening the Advanced Editor. Most people skip past it and go straight to writing M. Five clicks and you're done, and the M it generates is clean enough to modify later.
The analysts who get traction aren't the fastest at pulling data, they're the best at unpacking what was actually being asked. The skill is asking good questions, and nobody trains for it.
VLOOKUP and XLOOKUP, but for files that don't fit in memory, joins on multiple keys, and many-to-many matches that VLOOKUP simply can't do.
Automation bias is real: if you can automate something, it feels like you should. But some processes contain judgement calls that automation silently gets wrong, edge cases that require human revie…
You can't build every dashboard that gets requested. But 'no' lands differently depending on how you say it — and most data people either say yes to everything and resent it, or say no in ways that…
SUMIFS and COUNTIFS are great — until your data has 500,000 rows and Excel is grinding. Part 2 shows how to do everything your SUMIFS does, but with pandas groupby — faster, more flexible, and on d…
The more competent you get, the less people see the effort behind what you deliver. A clean dashboard looks effortless. A fast turnaround looks like it was always fast.
This isn't 'what is a variable' Python. This is: you have a CSV that's too big for Excel, you need it filtered by date and category, and you need the result saved as a clean file. Part 1 covers exa…
You deliver good work consistently, your manager knows you're reliable — and yet somehow you're invisible at promotion time. The problem isn't your output. It's that you've never made your work l…