week

week, data type

The week is a primitive data type, representing ISO weeks as the combination of a year and a week number within that year, such as 2001-W01 (the earliest week representable in Envision) or 2020-W45.

read "/Promo.ion" as Promotions with 
  StartWeek : week
  EndWeek : week

Date arithmetic is supported by the week type: weekA + 1 is the week right after weekA, and weekA - weekB is the number of weeks between weekA and weekB.

week(y: number, w: number) 🡒 week, const pure function

Returns a week with ISO week number w in year y ; will raise an error if the combination is incorrect.

show scalar "" with 
  week(2020, 45) // 2020-W45

week(d: date) 🡒 week, const pure function

Returns the week associated to the specified date.

show summary "" a1a3 with
  week(date(2019, 12, 28))
  week(date(2019, 12, 30))
  week(date(2020, 1, 1))

Week, special calendar table

The table Week is a special calendar table. This table can only be created with expect [date] in a read block, or by an unfiltering statement with span date =. When introduced, the Week table always has week as its primary dimension (of type week too).

With span:

span date = [date(2024, 1, 1) .. date(2024, 2, 28)]
  // 2-space of indent, we are within the 'span' block
  Week.X = random.uniform(1 into Week, 10 into Week)
  show linechart "Weekly" with Week.X

Or alternatively:

keep span date = [date(2024, 1, 1) .. date(2024, 2, 28)]
// no indent, as 'keep' is used
Week.X = random.uniform(1 into Week, 10 into Week)
show linechart "Weekly" with Week.X

A read block can also be used to introduce the Week table:

read "/sales.csv" as Sales expect [date] with // implicitely creates 'Week'
  "DateOfSales" as date : date // re-map the column originally named 'DateOfSales' to 'date'
  Qty : number

Week.Qty = sum(Sales.Qty) // 'Sales' is downstream of 'Week'
show linechart "Week" with Week.Qty

The Week table cannot be created via the usual means, such as table comprehensions for example.

week, primary dimension

The primary dimension of the table Week is named week, and it is of type week.

span date = [date(2024, 1, 1) .. date(2024, 2, 28)]
  // 2-space ident, we are within the 'span' block
  Week.X = random.poisson(5 into Week) // 5 is the mean, broadcast into 'Week'
  myWeek = week(2024, 2) // 2nd week of 2024
  show scalar "X on 2nd week" with Week.X[myWeek] // look-up on the primary dimension of 'Week'

If a table has date as a primary or secondary dimensions, it automatically receives week as a secondary dimension as well.