====== ISOWeekNumber(date) ======
Category:  Date and Time function

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=====Description=====
This function returns the [[https://en.wikipedia.org/wiki/ISO_week_date|ISO week number]] which ranges from 1 to 53 from //date//.

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=====Arguments=====
^Argument^Type^Description^
|date|Date or Number (date serial)|An expression that results in a date-time serial value.  The date to derive the ISO week number from.|

**Return value type:** Number.

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=====Remarks=====
The //date// argument can take any value or expression that evaluates to a date serial value.  Examples include:  
  * A date string:  #2019-12-12
  * A date serial value: 43811 (the date serial for "2019-12-12")
  * A date value created using any of the Date/Time functions that returns a date serial value.

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=====Examples=====

   isoweeknumber(#2018-06-06)  //Returns 23

   isoweeknumber(#2021-08-30)  //Returns 35