Java Calendar: I want to remove specific Day of week from calendar

Question

More details I want to get rid of specific days of the week.

I mean like: {Sat(1), Sun(2), Mon(3) , Tues(4) , Wed (5),Thurs(6) ,Fri(7)}.

Remove Week Days: {Sat(1), Sun(2), Mon(3) , Tues(4) , Wed (5)}.

So I can get the Count of days without the excluded days from the specific start date to the date of now.

Hint: I must Use the Java Calendar

The problem is specifying the day dynamically

Your question is kind of hard to understand. You want to count the number of Thursdays + Fridays between to dates? — OH GOD SPIDERS, Jul 26 '17 at 09:38
I want to get the count of days from specific from start date to end date excluding this two days — Mohamed Gabr, Jul 26 '17 at 09:39
Possible duplicate of [Calculate number of weekdays between two dates in Java](https://stackoverflow.com/questions/4600034/calculate-number-of-weekdays-between-two-dates-in-java) — Janar, Jul 26 '17 at 09:50
if your purpose is just counting number of days between 2 dates and without counting some specific days in week, I think this can help: https://stackoverflow.com/questions/4600034/calculate-number-of-weekdays-between-two-dates-in-java — Antony Dao, Jul 26 '17 at 09:51
Why do you have to use `Calendar`? Can't you use `LocalDate` ? — Krzysztof Atłasik, Jul 26 '17 at 10:03
Why do you want to exclude those 2 days? What are the conditions for removing them? — hamena314, Jul 26 '17 at 10:14
I want to exclude a specific number of days as i want to get the number of assigned days and non assigned days — Mohamed Gabr, Jul 26 '17 at 11:24
So you have a user that says "I don't like mondays, they dont count" (for whatever reason). And the user wants to know how many days are between a certain range, without those mondays? I.e.: "From 03/04/2017 to 05/07/2017 ... how many days are there without mondays"? Is this assumption correct? — hamena314, Jul 26 '17 at 12:09

Krzysztof Atłasik · Accepted Answer · 2019-02-11T08:11:57.003

7

If you can use LocalDate and stream you can apply a functional approach.

LocalDate start = LocalDate.of(2015, 2, 1);
LocalDate end = LocalDate.of(2015, 2, 28);

List<DayOfWeek> includedDays = Arrays.asList(DayOfWeek.THURSDAY, DayOfWeek.FRIDAY);

long daysCount = Stream.iterate(start, date -> date.plusDays(1))
        .limit(ChronoUnit.DAYS.between(start, end))
        .filter(d -> includedDays.contains(d.getDayOfWeek()))
        .count();

If you insist on calendar just use:

GregorianCalendar calendarStart = new GregorianCalendar(2015, 2, 1);
GregorianCalendar calendarEnd = new GregorianCalendar(2015, 2, 28);

List<Integer> includedDays = Arrays.asList(GregorianCalendar.THURSDAY, GregorianCalendar.FRIDAY);
long count = 0;
while(!calendarStart.equals(calendarEnd)) {
    if(includedDays.contains(calendarStart.get(Calendar.DAY_OF_WEEK))) {
        count ++;
    }
    calendarStart.add(Calendar.DATE, 1);
}

edited Feb 11 '19 at 08:11

answered Jul 26 '17 at 10:07

Krzysztof Atłasik

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the days will be added dynamically not static days – Mohamed Gabr Jul 26 '17 at 10:10
1

Can't you just create dynamic list for `includedDays`? – Krzysztof Atłasik Jul 26 '17 at 10:16
its included dynamically from the user from a front end interface – Mohamed Gabr Jul 26 '17 at 11:23
Setting the day dynamically is the problem – Mohamed Gabr Jul 26 '17 at 11:54
2

Alright, so you have to dynamically transform it to list. How do you expect me to give you more precise answer if you didn't show how data comes in from frontend? – Krzysztof Atłasik Jul 26 '17 at 11:55
it comes as Array of ints – Mohamed Gabr Jul 26 '17 at 11:56
as the the calendar days start from 1 and end to 7 – Mohamed Gabr Jul 26 '17 at 11:57
1

This list is just example assuming you would like to include Thursday and Friday. `GregorianCalendar.THURSDAY` is constant from class `GregorianCalendar` with value `5` and `GregorianCalendar.FRIDAY` is `6`. List `includedDays` is already list of ints, so you will have just to use your data instead of this hardcoded example. – Krzysztof Atłasik Jul 26 '17 at 12:08
3

@Eng.Gabr This would be **a lot** easier if you would provide some example code. Apart from that i really don't see what the problem is in converting an array of ints to a list of Integers. – OH GOD SPIDERS Jul 26 '17 at 12:08
And this is what I canot solve conditioning either the number is equal to `Calendar.THURSDAY` equals to 5 or not to push the value of these days to the calendar – Mohamed Gabr Jul 26 '17 at 12:39
1

`Calendar.THURSDAY` is just constant with value 5. Line of code where list is created, could be written as: `Arrays.asList(new int[]{5, 6});` Instead of hardcoded `new int[]{5,6};` just use your data from frontend. – Krzysztof Atłasik Jul 26 '17 at 12:57
@RandallFlagg Thank you very much – Mohamed Gabr Jul 26 '17 at 13:00
1

I just recognized that you are mentioning List of integers – Mohamed Gabr Jul 26 '17 at 13:00

Java Calendar: I want to remove specific Day of week from calendar

1 Answers1