I want to get number of weeks in a particular month

Question

i want to get number of weeks in current month.That including the previous month\'s days in the last week and the first week days in the next month.

Something like t

Answer 1

if you want to do it by "hand"

use this:

Date.prototype.getMonthWeek = function(monthAdjustement)
{    

    var firstDay = new Date(this.getFullYear(), this.getMonth(), 1).getDay();

    var returnMessage = (Math.ceil(this.getDate()/7) + Math.floor(((7-firstDay)/7)));

    return returnMessage;

}

Where monthAdjustement is just an Integer adjusting the month you seek compared to Today's date.

Answer 2

We can use the calendar class and then do something like

Calendar calendar = Calendar.getInstance();
System.out.println(calendar.getActualMaximum(Calendar.WEEK_OF_MONTH));

this will return the number of weeks in the current month

Answer 3

use WEEK_OF_MONTH will be better, no cross year issue.

public static void main(String[] args) throws Exception {
  for (String m : new String[] { "2012-11", "2012-12", "2013-01", "2013-02", "2013-03",
              "2013-04", "2013-05", "2013-06" }) {
      SimpleDateFormat format = new SimpleDateFormat("yyyy-MM");
      Date date = format.parse(m);
      Calendar c = Calendar.getInstance();
      c.setTime(date);

      int start = c.get(Calendar.WEEK_OF_MONTH);

      c.add(Calendar.MONTH, 1);
      c.add(Calendar.DATE, -1);
      int end = c.get(Calendar.WEEK_OF_MONTH);
      System.out.println(" # of weeks in " + format.format(c.getTime())
              + ": " + (end - start + 1));
  }
}

results:

# of weeks in 2012-11: 5
# of weeks in 2012-12: 6
# of weeks in 2013-01: 5
# of weeks in 2013-02: 5
# of weeks in 2013-03: 6
# of weeks in 2013-04: 5
# of weeks in 2013-05: 5
# of weeks in 2013-06: 6

Answer 4

The WEEK_OF_YEAR attribute of the Calendar class can be useful for you. Ref: Calendar class

Create a new date that will be the first day of the some month. Get the week of the year for this day, let say you got start value.

Create a new date that will be the last day of the given month. Get the week of the year for this day, so now you got end value.

Now end - start + 1 should be one that you want.

You may have to handle some corner case when the week overlaps to another year or similar. But I think once you get this right, you can do that with simple logic.

Here is simple example code. I think you can make it into function and pass whatever you want.

        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, 2013);
        cal.set(Calendar.MONTH, 1);
        cal.set(Calendar.DAY_OF_MONTH, 1);
        int start = cal.get(Calendar.WEEK_OF_YEAR);
        Log.d("BLA BLA", "Value is " + start);
        cal.set(Calendar.YEAR, 2013);
        cal.set(Calendar.MONTH, 1);
        cal.set(Calendar.DAY_OF_MONTH, 28);
        int end = cal.get(Calendar.WEEK_OF_YEAR);
        //Above line will not work for December Month, use following line for this
        int end = isDecember?53:cal.get(Calendar.WEEK_OF_YEAR);
        Log.d("BLA BLA", "Value is " + end);
        Log.d("BLA BLA", "Num weeks:: " + (end - start +1 ));

For Corner case:

Corner case will only occur for the month of Januaray (E.g Jan 2010, Jan 2000) in those cases most of the days are part of the last week of the previous year so the start value will be 52 and end value will be 5. When this occurs check if,

          if(start > end) {
                numweeks = end + 1;
             }

P.S: Put it to different testing inputs that you got. Let me know If I can improve on it once you find any fault.

And Even much simpler solution:

        Calendar cal = Calendar.getInstance();
        for(int i = 0 ; i < 11;i++){
            cal.set(Calendar.YEAR, 2013);
            cal.set(Calendar.DAY_OF_MONTH, 1);
            cal.set(Calendar.MONTH, i);
            int maxWeeknumber = cal.getActualMaximum(Calendar.WEEK_OF_MONTH);
            Log.d("LOG","max week number" + maxWeeknumber);
        }

        01-22 01:49:03.591: D/LOG(573): max week number5
        01-22 01:49:03.602: D/LOG(573): max week number5
        01-22 01:49:03.602: D/LOG(573): max week number6
        01-22 01:49:03.671: D/LOG(573): max week number5
        01-22 01:49:03.671: D/LOG(573): max week number5
        01-22 01:49:03.671: D/LOG(573): max week number6
        01-22 01:49:03.681: D/LOG(573): max week number5
        01-22 01:49:03.691: D/LOG(573): max week number5
        01-22 01:49:03.691: D/LOG(573): max week number5
        01-22 01:49:03.711: D/LOG(573): max week number5
        01-22 01:49:03.711: D/LOG(573): max week number5

Simple solution works fine with corner cases:

        Calendar cal = Calendar.getInstance();
        for(int i = 0 ; i < 11;i++){
            cal.set(Calendar.YEAR, 2010);
            cal.set(Calendar.DAY_OF_MONTH, 1);
            cal.set(Calendar.MONTH, i);
            int maxWeeknumber = cal.getActualMaximum(Calendar.WEEK_OF_MONTH);
            // Month value starts from 0 to 11 for Jan to Dec
            Log.d("LOG","For Month :: "+ i + " Num Week :: " + maxWeeknumber);
        }

Log:

        01-22 01:59:35.841: D/LOG(629): For Month :: 0 Num Week :: 6
        01-22 01:59:35.841: D/LOG(629): For Month :: 1 Num Week :: 5
        01-22 01:59:35.841: D/LOG(629): For Month :: 2 Num Week :: 5
        01-22 01:59:35.841: D/LOG(629): For Month :: 3 Num Week :: 5
        01-22 01:59:35.841: D/LOG(629): For Month :: 4 Num Week :: 6
        01-22 01:59:35.852: D/LOG(629): For Month :: 5 Num Week :: 5
        01-22 01:59:35.871: D/LOG(629): For Month :: 6 Num Week :: 5
        01-22 01:59:35.871: D/LOG(629): For Month :: 7 Num Week :: 5
        01-22 01:59:35.871: D/LOG(629): For Month :: 8 Num Week :: 5
        01-22 01:59:35.871: D/LOG(629): For Month :: 9 Num Week :: 6
        01-22 01:59:35.871: D/LOG(629): For Month :: 10 Num Week :: 5

Answer 5

Let's assume we know the first day of the month (Saturday, Sunday etc).

• If 1st day of the month is a Sunday and it's not a leap-year, then the (correction edit) February month will have only 4 weeks. Otherwise, in all the cases, it should have at least 5 and at most 6 weeks.
• Now, if your month starts on Saturday, you'll always have 6 weeks (excluding if it is February, when it there will be 5)
• Now, if your month starts on Friday, you'll have 6 weeks for months having 31 days and 5 for all others.
• For rest of the cases, it will always be 5 weeks.

Finding out the 1st day of the month shouldn't be difficult, you can use Calendar or other date/time utility library classes. However, I guess there could be cleaner solutions removing the corner cases and unnecessary complexity.