Use the new dt.dayofweek property: In [2]: df[‘weekday’] = df[‘Timestamp’].dt.dayofweek df Out[2]: Timestamp Value weekday 0 2012-06-01 00:00:00 100 4 1 2012-06-01 00:15:00 150 4 2 2012-06-01 00:30:00 120 4 3 2012-06-01 01:00:00 220 4 4 2012-06-01 01:15:00 80 4 In the situation where the Timestamp is your index you need to reset the index … Read more
SQL> SELECT TO_CHAR(date ‘1982-03-09’, ‘DAY’) day FROM dual; DAY ——— TUESDAY SQL> SELECT TO_CHAR(date ‘1982-03-09’, ‘DY’) day FROM dual; DAY — TUE SQL> SELECT TO_CHAR(date ‘1982-03-09’, ‘Dy’) day FROM dual; DAY — Tue (Note that the queries use ANSI date literals, which follow the ISO-8601 date standard and avoid date format ambiguity.)
Use day1 = (int)ClockInfoFromSystem.DayOfWeek;
I would strongly recommend using Joda Time instead (for all your date/time work, not just this): // TODO: Consider time zones, calendars etc LocalDate now = new LocalDate(); LocalDate monday = now.withDayOfWeek(DateTimeConstants.MONDAY); System.out.println(monday); Note that as you’ve used Monday here, which is the first day of the week in Joda Time, this will always return … Read more
The following function will return all Mondays for the current month: function getMondays() { var d = new Date(), month = d.getMonth(), mondays = []; d.setDate(1); // Get the first Monday in the month while (d.getDay() !== 1) { d.setDate(d.getDate() + 1); } // Get all the other Mondays in the month while (d.getMonth() === … Read more
Let’s do some tunning. Prime factorization of TimeSpan.TicksPerDay (864000000000) : DayOfWeek now can be expressed as: public DayOfWeek DayOfWeek { get { return (DayOfWeek)(((Ticks>>14) / 52734375 + 1L) % 7L); } } And we are working in modulo 7, 52734375 % 7 it’s 1. So, the code above is equal to: public static DayOfWeek dayOfWeekTurbo(this … Read more
Those fields does not return the values. Those are constants which identifies the fields in the Calendar object which you can get/set/add. To achieve what you want, you first need to get a Calendar, clear it and set the known values. It will automatically set the date to first day of that week. // We … Read more
Well, you can tell just by looking at it that it is correct… Assuming that the t[] array is correct, which you can verify with just 12 spot checks (one for each month using any day/year). The y -= m < 3 is a nice trick. It creates a “virtual year” that starts on March … Read more
The first day of the week is based on your language settings of the server. The default setting for us_english is 7 (Sunday) You can find the current first day of the week by using SELECT @@DATEFIRST However, you can use DATEFIRST for this. Just put it at the top of your query SET DATEFIRST … Read more
Use this function, comes with date string validation: If you include this function somewhere in your project, // Accepts a Date object or date string that is recognized by the Date.parse() method function getDayOfWeek(date) { const dayOfWeek = new Date(date).getDay(); return isNaN(dayOfWeek) ? null : [‘Sunday’, ‘Monday’, ‘Tuesday’, ‘Wednesday’, ‘Thursday’, ‘Friday’, ‘Saturday’][dayOfWeek]; } You will … Read more