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5.4.6.21. weekNumber

Returns the timestamp's ISO week number.

Any given year will have week numbers either between 1 and 52, or between 1 and 53.

See also methods weekNumberYear, weekNumberDate, and weeksInYear.

Example 5.232. DateTime class — weekNumber method 
say weekNumber(2018, 12, 31)    -- 1 2019-W01-1
say weekNumber(2019,  1,  1)    -- 1 2019-W01-2

say weekNumber(2020, 12, 31)    -- 53 2020-W53-4
say weekNumber(2021,  1,  1)    -- 53 2020-W53-5
return

weekNumber: procedure
  date = .DateTime~new(arg(1), arg(2), arg(3))
  return date~weekNumber date~weekNumberDate