LibreOffice 25.2 ヘルプ
WEEKNUM calculates the week number of the year for the internal date value as defined in ODF OpenFormula and compatible with other spreadsheet applications.
Supported are two week numbering systems:
| システム | 概要 | 
|---|---|
| System 1 | The week containing January 1 is the first week of the year, and is numbered week 1. | 
| System 2 | The week containing the first Thursday of the year is the first week of the year, and is numbered week 1. That means that week number 1 of any year is the week that contains January 4th. ISO 8601 defines this system and that the week starts on Monday. | 
WEEKNUM(数値; モード)
数値 には日付のシリアル値を入力します。
Mode sets the start of the week and the week numbering system. This parameter is optional, if omitted the default value is 1.
| システム | モード | Day of the week | 
|---|---|---|
| System 1 | 1 | Sunday | 
| 2 | 月曜日 | |
| 11 | 月曜日 | |
| 12 | 火曜日 | |
| 13 | 水曜日 | |
| 14 | 木曜日 | |
| 15 | 金曜日 | |
| 16 | 土曜日 | |
| 17 | Sunday | |
| System 2 | 21 | Monday (ISO 8601) | 
| 150 | (ISO 8601, for interoperability with Gnumeric) | 
=WEEKNUM(DATE(1995;1;1);1) returns 1
=WEEKNUM(DATE(1995;1;1);2) returns 1. Using System 1, the week containing January 1 is the first week of the year.
=WEEKNUM(DATE(1995;1;1);21) returns 52. Week 1 starts on Monday, 1995-01-02.
=WEEKNUM(DATE(1999;1;1);21) returns 53. Week 1 starts on Monday, 1999-01-04.