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Your time-series has missing days, breaking moving averages and forecasts. Fill the gaps with a date spine.

Days with zero events simply don't appear in an event table, so a 7-day average silently averages the wrong 7 rows. A date spine makes the missing days explicit. Here is the pattern.

Updated Aug 2026 · Grounded in real Applied AI Engineer interview loops and written to a senior-engineer editorial bar.

Days with zero events simply don't appear in an event table, so a 7-day average silently averages the wrong 7 rows. A date spine makes the missing days explicit. Here is the pattern.

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