Extended Date Table (Power Query M function)

Power Query M Code Showcase
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Hi @kjssdca,

Thanks for your question.

By default the Power Query Date.DayOfWeek function returns a number between 0 and 6 starting on Sunday. To return the weekday number according to ISO8601 rules, you have to add the optional first-weekday value (= Day.Monday) and change the numbering so it runs between 1 and 7.
This explains the +1

The +10 / 7 is part of the algorithm for calculating the week number, you can find more on that here.

If you need assistance creating a customized week number, please create a new topic. You’ll find that there’s an increasing number of active members here who’d like to help out. :wink:

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