However, the ISO 8601 calendar standard, widely used in Europe, defines the first week as the one with the majority of days (four or more) falling in the new year. See Remarks.īy default, the WEEKNUM function uses a calendar convention in which the week containing January 1 is considered to be the first week of the year. (Optional) A number that determines on which day the week begins. This system is the methodology specified in ISO 8601, which is commonly known as the European week numbering system. System 2 - The week containing the first Thursday of the year is the first week of the year and is numbered as week 1.System 1 - The week containing January 1 is the first week of the year and is numbered week 1.There are two systems used for this function: The week number indicates where the week falls numerically within a year. The format characters for the two different years are either Y or o and they should not be confused.Returns the week number for the given date according to the return_type value. In the Gregorian 1 calendar with year, month and day (of month), and in the ISO 8601 calendar with year, week and day (of week). In 2018 the ISO year and calendar year start on the same date- or 2018-W01-1.Īs conlusion, this article shows that there are two ways representing dates in PHP. Week 53 in ISO year 2015 goes from Monday to Sunday The next year for which the ISO year has 53 weeks is 2015: format('Y-\WW-N'), "\n" In every 400 years there are 71 years with 53 weeks (and 329 years with 52 weeks). This is because a year is 52 weeks and one day (or two days for leap years). In most ISO 8601 years, there are 52 weeks. The ISO week date 2014-W01-2 is part of calendar year 2013. Parsing an ISO year/week/day combination displays the same issues: format("Y-m-d"), "\n" To show the ISO 8601 year, you need to use the o specifier. The Y format specifier gives the calendar year which is not the same as the ISO 8601 year. If you do the following in PHP, you get an unexpected answer: format('Y-\WW-N'), "\n" The ISO year starts with (ISO) week 1, day 1, which is always a Monday. As you see with December 31st, the ISO 8601 year ( 2014) is not the same as the calendar year ( 2013). Examples are: 2013-W39-2 for today and 2013-W40 for next Monday. It is also possible to omit the day-of-week ( yyyy "W" ww) to represent the start of the week (Monday) and to add - in the format (such as in yyyy "-W" ww "-" d. PHP supports the formats yyyy "W" wwĭ where yyyy is the ISO 8601 year, "W" a delimiter, ww the week number and d the day of the week (with 1 being Monday, and 7 being Sunday). ![]() With the year number (2012, 2013, etc), the week number (01-53) and the day number (1-7) you can describe a day. ![]() ![]() Week number 1 of each year is the first week in a year that has the first Thursday of the year, or in other words, the week containing January 4th. ![]() Each year has 52 or 53 weeks and weeks always start on a Monday. Week numbers are defined in this same ISO 8601 standard. In the past few weeks I've seen a few bug reports in the PHP bug system ( 6560) that deal with another aspect of this same calendar: week numbers. Back in 2009 I wrote that PHP calendar implementation uses the ISO 8601 calendar for year numbers.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |