Delphi Basics : DayOfTheWeek command

DelphiBasics

DayOfTheWeek
Function

Gives day of week index for a TDateTime value (ISO 8601)

DateUtils unit

function DayOfTheWeek(const Date TDateTime):Integer;

Description

The DayOfTheWeek function returns an index number for the day of the week :

1	= Monday
2	= Tuesday
3	= Wednesday
4	= Thursday
5	= Friday
6	= Saturday
7	= Sunday

Notes

DayOfTheWeek is ISO 8601 compliant, since it uses Monday as the start of the week.

DayOfWeek is not compliant - it treats Sunday as the starting day.

Related commands

DayOfTheMonth		Gives day of month index for a TDateTime value (ISO 8601)
DayOfTheYear		Gives the day of the year for a TDateTime value (ISO 8601)
DayOfWeek		Gives day of week index for a TDateTime value
MonthOfTheYear		Gives the month of the year for a TDateTime value

Download this web site as a Windows program.

Example code : Show the day of the week for Christmas 2002

var
  myDate : TDateTime;
  day    : array[1..7] of string;

begin
  // We cannot use LongDayNames - they start on Sunday
  day[1] := 'Monday';
  day[2] := 'Tuesday';
  day[3] := 'Wednesday';
  day[4] := 'Thursday';
  day[5] := 'Friday';
  day[6] := 'Saturday';
  day[7] := 'Sunday';

  myDate := EncodeDate(2002, 12, 25);

  ShowMessage('Christmas day 2002 is on a '+day[DayOfTheWeek(myDate)]);
end;

Show full unit code

Christmas day 2002 is on a Wednesday