LibreOffice 25.2 ヘルプ
This function returns the number corresponding to the weekday represented by a serial date number that is generated by the DateSerial or the DateValue functions.
This help page describes the WeekDay function used in Basic scripts. If you are interested in the WeekDay function used in LibreOffice Calc, refer to this help page.
  WeekDay (SerialDate, [FirstDayOfWeek])
SerialDate: Integer expression that contains the serial date number that is used to calculate the day of the week.
FirstDayOfWeek: Integer value indicating which weekday should be considered as the first day of the week. The default value is 0, meaning that the system locale settings are used to determine the first day of the week.
The parameter FirstDayOfWeek accepts values ranging from 0 to 7. The table below describes the meaning of each possible value:
| 値 | VBA Constant | 概要 | 
|---|---|---|
| 0 | vbUseSystemDayOfWeek | Use system locale settings | 
| 1 | vbSunday | 日曜日 (デフォルト) | 
| 2 | vbMonday | 月曜日 | 
| 3 | vbTuesday | 火曜日 | 
| 4 | vbWednesday | 水曜日 | 
| 5 | vbThursday | 木曜日 | 
| 6 | vbFriday | 金曜日 | 
| 7 | vbSaturday | 土曜日 | 
The VBA constants listed above are only available if VBA support has been enabled. For more information, read the VBASupport Statement help page.
整数
The following example uses the function Now() to determine the current weekday.
Sub ExampleWeekDay
    Dim sDay As String
    REM 本日の曜日の取得と表示
    Select Case WeekDay( Now )
            Case 1: sDay="Sunday"
            Case 2: sDay="Monday"
            Case 3: sDay="Tuesday"
            Case 4: sDay="Wednesday"
            Case 5: sDay="Thursday"
            Case 6: sDay="Friday"
            Case 7: sDay="Saturday"
    End Select
    msgbox "" + sDay,64,"Today is"
End Sub
The following example illustrates the use FirstDayOfWeek parameter, assuming that Tuesday is the first day of the week.
  Dim someDay As Long
  ' The date January 1st 2021 was a Friday
  someDay = DateSerial(2021, 01, 01)
  ' Prints "6" assuming Sunday is the first day of the week
  MsgBox WeekDay(someDay)
  ' Prints "4" assuming Tuesday is the first day of the week
  MsgBox WeekDay(someDay, 3)