How to calculate Current Calendar Week Number
Below are examples of getting current calendar week number in many languages, like: Java, PHP, Perl, SQL (Oracle, MySQL, MS SQL), Python, Ruby
Java
java.util.Calendar.getInstance().get(java.util.Calendar.WEEK_OF_YEAR);
Perl
my $weekNumber = POSIX::strftime("%V", gmtime time);
Replace time with other UNIX timestamps for other week numbers.
PHP
$weekNumber = date("W");
or date("W", epoch) for other week numbers. Remember to use capital 'W' not 'w'.
MySQL
SELECT WEEKOFYEAR(NOW())
Replace now() with other dates eg. SELECT WEEKOFYEAR('2008-02-20');
(You can also use the WEEK function with mode=3 select week(now(),3))
MS SQL
SELECT DATEPART( wk, GETDATE() )
iPhone/Mac
[NSString stringWithFormat:@"Week %d", [calendar ordinalityOfUnit:NSWeekCalendarUnit inUnit:NSYearCalendarUnit forDate:date]];
Python
import time
week_number_as_string = time.strftime("%W")
week_number = int(week_number_as_string)
Ruby
week_number = Time.now.strftime("%U")
Replace Time.now with Time.local(year,month,day) for other dates.
Formats:
%U - Week number of the year, starting with the first Sunday as the first day of the first week (00..53)
%V - Week number of year according to ISO 8601 (01..53)
%W - Week number of the year, starting with the first Monday as the first day of the first week (00..53)
Microsoft Excel
=WEEKNUM(A1)-1Week numbers can vary based on your locality settings (not ISO-8601!). See discussion below.
Unix/Linux
date +%W