Get Weekdays Within a Month

Get weekdays within a month

With the help of this answer, I was able to accomplish this.

let calendar = NSCalendar.currentCalendar()
let normalizedStartDate = calendar.startOfDayForDate(NSDate().startOfMonth)
let normalizedEndDate = calendar.startOfDayForDate(NSDate().endOfMonth)

var dates = [normalizedStartDate]
var currentDate = normalizedStartDate
repeat {
    currentDate = calendar.dateByAddingUnit(NSCalendarUnit.Day, value: 1, toDate: currentDate, options: .MatchNextTime)!
    dates.append(currentDate)
} while !calendar.isDate(currentDate, inSameDayAsDate: normalizedEndDate)

let weekdays = dates.filter { !calendar.isDateInWeekend($0) }
weekdays.forEach { date in
    print(NSDateFormatter.localizedStringFromDate(date, dateStyle: .FullStyle, timeStyle: .NoStyle))
}

And it works!

Monday, February 1, 2016
Tuesday, February 2, 2016
Wednesday, February 3, 2016
Thursday, February 4, 2016
Friday, February 5, 2016
Monday, February 8, 2016
Tuesday, February 9, 2016
Wednesday, February 10, 2016
Thursday, February 11, 2016
Friday, February 12, 2016
Monday, February 15, 2016
Tuesday, February 16, 2016
Wednesday, February 17, 2016
Thursday, February 18, 2016
Friday, February 19, 2016
Monday, February 22, 2016
Tuesday, February 23, 2016
Wednesday, February 24, 2016
Thursday, February 25, 2016
Friday, February 26, 2016
Monday, February 29, 2016

How to get all dates and weekdays in current month in flutter

The lastDayOfMonth is a single date, therefore using lastDayOfMonth.weekDay gives a single day based on lastDayOfMonth. We can add duration on lastDayOfMonth and find day name.

 final currentDate =
           lastDayOfMonth.add(Duration(days: index + 1));

This will provide update date based on index. I am using intl package or create a map to get the day name.

A useful answer about date format.

 Row(
  children: List.generate(
    lastDayOfMonth.day,
    (index) => Padding(
      padding: const EdgeInsets.only(right: 24.0),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Text(
            "${index + 1}",
          ),
          () {
            final currentDate =
                lastDayOfMonth.add(Duration(days: index + 1));

            final dateName =
                DateFormat('E').format(currentDate);
            return Text(dateName);
          }()
        ],
      ),
    ),
  ),
),

How would I get the amount of weekdays in a month with LocalDate - Java

If desired, see optimized brute-force solution at the end

Here is a non-brute-force implementation to calculate week days (Mon-Fri) in a month.

It uses YearMonth instead of LocalDate, since the day-of-month value is meaningless to the calculation.

public static int weekDaysInMonth(YearMonth yearMonth) {
    int len = yearMonth.lengthOfMonth(); // 28-31, supporting leap year
    int dow = yearMonth.atDay(1).getDayOfWeek().getValue(); // 1=Mon, 7=Sun
    return (dow <= 5 ? Math.min(len - 8, 26 - dow) : Math.max(len + dow - 16, 20));
}

Here is an overload taking a LocalDate, so it's easy to call if that's what you have.

public static int weekDaysInMonth(LocalDate date) {
    return weekDaysInMonth(YearMonth.from(date));
}

Test

System.out.println(weekDaysInMonth(LocalDate.parse("2018-04-15"))); // April 15, 2018
System.out.println(weekDaysInMonth(YearMonth.of(2018, 5)));         // May 2018

Output

21
23

---

Explanation of Formula

The formula in the return statement was created by examining the expected return value for every combination of len (number of days in month, 28 - 31) and dow (day-of-week of first day of month, 1=Mon - 7=Sun):

   |  1   2   3   4   5    6   7
   | Mo  Tu  We  Th  Fr   Sa  Su
---+----------------------------
28 | 20  20  20  20  20   20  20
29 | 21  21  21  21  21   20  20
30 | 22  22  22  22  21   20  21
31 | 23  23  23  22  21   21  22

Explanation for dow <= 5 (Mon-Fri)

Initially there are len - 8 weekdays, i.e. we subtract the 4 weekends that always exist in a month.

As we get to Thursday and Friday, we need to cap that for the 1 or 2 weekend days we lose. If you look at the 31-day row, we cap it at 26 - dow, i.e. for Friday (dow=5) we cap at 21, and for Thursday (dow=4) we cap at 22. For Monday-Wednesday, we also cap, but cap is equal to or higher than initial calculation, so it doesn't matter.

Capping is done using min(xxx, cap) method, so we get:

min(len - 8, 26 - dow)

Explanation for dow >= 6 (Sat-Sun)

You can see a small triangle in the lower-right corner. If we extend that pattern, we get:

   |  4   5   6   7
---+---------------
28 | 16  17  18  19
29 | 17  18  19  20
30 | 18  19  20  21
31 | 19  20  21  22

As a formula, that is len + dow - 16.

Comparing that to original grid, numbers bottom out at 20, which is done using max(xxx, bottom) method, so we get:

max(len + dow - 16, 20)

Conclusion

Finally we combine the two using ternary conditional operator:

dow <= 5  ?  min(len - 8, 26 - dow)  :  max(len + dow - 16, 20)

Full Java statement is then:

return (dow <= 5 ? Math.min(len - 8, 26 - dow) : Math.max(len + dow - 16, 20));

---

Brute-Force Solution

If you prefer a brute-force solution, you can ease it by skipping the first 4 weeks that always exists in a month:

public static int weekDaysInMonth(LocalDate refDate) {
    LocalDate firstOfMonth = refDate.withDayOfMonth(1);
    LocalDate nextMonth = firstOfMonth.plusMonths(1);
    int days = 20;
    for (LocalDate date = firstOfMonth.plusDays(28); date.isBefore(nextMonth); date = date.plusDays(1))
        if (date.getDayOfWeek().getValue() <= 5) // 1=Mon - 5=Fri, i.e. not 6=Sat and 7=Sun
            days++;
    return days;
}

Get number of weekdays in a given month

Some basic code:

$month = 12;
$weekdays = array();
$d = 1;

do {
    $mk = mktime(0, 0, 0, $month, $d, date("Y"));
    @$weekdays[date("w", $mk)]++;
    $d++;
} while (date("m", $mk) == $month);

print_r($weekdays);

Remove the @ if your PHP error warning doesn't show notices.

print first 10 working days in a month using python

Here's an example:

import datetime

date = datetime.datetime.strptime("MAR-21", "%b-%y")
weekdaycount = 0
while weekdaycount < 10:
    if date.weekday() in [0,1,2,3,4]:
        print(date)
        weekdaycount += 1
    date += datetime.timedelta(days=1)

how to get weekday and weekend count for months?

Use EXTRACT with the date part isodow. This returns a value of 1 to 7 for Monday through Sunday.

SELECT
    u.fname, 
    MONTH(e.eventDate),
    COUNT(*) FILTER (WHERE EXTRACT(idodow FROM e.eventDate) < 6) AS WeekdayCount,
    COUNT(*) FILTER (WHERE EXTRACT(idodow FROM e.eventDate) IN (6, 7)) AS WeekendCount,
FROM users u
LEFT JOIN eventcal e ON e.primary = u.username
GROUP BY
    u.fname,
    MONTH(e.eventDate);

Note also that a left join from users to the eventcal table would seem to make the most sense here, not the reverse.

How to get a list of week days in a month?

Well, how about:

public static List<DateTime> GetDates(int year, int month)
{
   return Enumerable.Range(1, DateTime.DaysInMonth(year, month))
                    .Select(day => new DateTime(year, month, day))
                    .Where(dt => dt.DayOfWeek != DayOfWeek.Sunday &&
                                 dt.DayOfWeek != DayOfWeek.Saturday)
                    .ToList();
}

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