Power Fx function
Complete A–Z reference
ISOWeekNum
ISO calendar week of a date.
What it does
ISO calendar week of a date.
The job: Every function, signal, and operator entry in the canvas-apps reference.
How to use ISOWeekNum
Start from the task, not the alphabet. If you are shaping rows for a gallery, reach for ISOWeekNum alongside the other data functions in its group; if you are saving, navigating, or changing state, use it on an event such as a button OnSelect rather than in a display property. When a formula misbehaves, check for a blank value where you expected text, then confirm the behaviour against the examples in the Power Fx function reference hub.
New to the language itself? Read What Is Microsoft Power Fx? first, then come back here when you need this specific tool.