Page tree

The cloud-based product Trifacta Free is available now! Register for your free account.

 

Derives the numeric value for the week within the year (1, 2, etc.). Input must be the output of the DATE function or a reference to a column containing Datetime values. The output of this function increments on Sunday.

Week 1 of the year is the week that contains January 1.

NOTE: If the source Datetime value does not include a valid input for this function, a missing value is returned.

Wrangle vs. SQL: This function is part of Wrangle , a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.

Basic Usage

Column reference example:

weeknum(MyDate)

Output: Returns the numeric week number values derived from the MyDate column.

Syntax and Arguments

weeknum(datetime_col)


ArgumentRequired?Data TypeDescription
datetime_colYdatetimeName of column whose week number values are to be computed

For more information on syntax standards, see Language Documentation Syntax Notes.

datetime_col

Name of the column whose week number value is to be computed.

  • Missing values for this function in the source data result in missing values in the output.
  • Multiple columns and wildcards are not supported.

Tip: You cannot insert constant Datetime values as inputs to this function. However, you can use the following: WEEKNUM(DATE(2017,12,20)) .

Usage Notes:

Required?Data TypeExample Value
YesDatetimemyDate

Examples

Tip: For additional examples, see Common Tasks.

Example - Day of Date functions

This example illustrates how you can apply functions to derive day-of-week values out of a column of Datetime type:
  • WEEKDAY - returns numeric value for the day of the week for source Datetime values. See WEEKDAY Function
  • WEEKNUM - returns the numeric value for the week within the year for source Datetime values. See WEEKNUM Function.
  • DATEFORMAT - can be used to format Datetime values in many different ways. See DATEFORMAT Function.

Source:

myDate
10/30/17
10/31/17
11/1/17
11/2/17
11/3/17
11/4/17
11/5/17
11/6/17


Transformation:

The following transformation step generates a numeric value for the day of week in a new column:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula WEEKDAY (myDate)
Parameter: New column name 'weekDayNum'

The following step generates a full text version of the name of the day of the week:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula DATEFORMAT(myDate, 'EEEE')
Parameter: New column name 'weekDayNameFull'

The following step generates a three-letter abbreviation for the name of the day of the week:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula DATEFORMAT(myDate, 'EEE')
Parameter: New column name 'weekDayNameShort'

The following step generates the numeric value of the week within the year:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula WEEKNUM (myDate)
Parameter: New column name 'weekNum'

Results:

myDateweekDayNumweekDayNameFullweekDayNameShortweekNum
10/30/171MondayMon44
10/31/172TuesdayTue44
11/1/173WednesdayWed44
11/2/174ThursdayThu44
11/3/175FridayFri44
11/4/176SaturdaySat44
11/5/177SundaySun45
11/6/171MondayMon45

 

This page has no comments.