Aweek

aweek returns the first day of a week number for the year.

Syntax

  aweek(EXPR_WEEK,EXPR_YEAR)

• EXPR_WEEK is an integer expression that returns the week number.
• EXPR_YEAR is an integer expression that returns the year number between 1600 and 9999, or between 0 and 99.

Examples

   # Let's give the date that corresponds to the first Wednesday of the current week.
    WEDN_DATE = aweek(37,year(date$))+2
   # Other examples
    DATE1=aweek(-1,2013) : # Corresponds to [17/12/2012]
    DATE2=aweek(0,16) : # Corresponds to [04/01/2016] if adxdcs is greater than 1916

Description

The function aweek calculates the date of the first day (Monday) for a week number in a year. The type of the result is Date.

The week is numbered from 0 to 53. The calculation mode follows the NF ISO 8601 norm and is as follows:

• A week starts on Monday (day 1) and ends on Sunday (day 7).
• The first week of a year is the week that contains the first Thursday of the year. If the first day of the year is a Friday, a Saturday, or a Sunday, a week numbered 0 exists that starts the first of January and ends the next Sunday.
• When the year is only two digits, the year used depends on the value of adxdcs.
• If a negative value of the week is given, the calculation goes back to the previous week of the previous year.

Associated errors

Error	Description
10	The argument is not a string.
56	Incorrect data values (year not in the acceptable range).

See also

Date, week, day, day$, month, year, nday, nday$, adxdcs.