定义一个时期

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How many working days in year 2021?

Here is the detail of the calculation:

Because 2021 is not a leap year, it has 365 days.

Let's remove 52 saturdays and 52 sundays. It remains 261 days.

Now, let's remove 12 public holidays that do not fall during a weekend and we obtain 249 working days in 2021.

Here is the list of these 12 public holidays:

1. New Year's Day : 星期五, 2021, 01, 1
2. Martin Luther King Day : 星期一, 2021, 01, 18
3. President's Day : 星期一, 2021, 02, 15
4. Memorial Day : 星期一, 2021, 05, 31
5. Juneteenth Observance : 星期五, 2021, 06, 18
6. Independence Day Observance : 星期一, 2021, 07, 5
7. Labor Day : 星期一, 2021, 09, 6
8. Columbus Day : 星期一, 2021, 10, 11
9. Veterans Day : 星期四, 2021, 11, 11
10. Thanksgiving : 星期四, 2021, 11, 25
11. Christmas Observance : 星期五, 2021, 12, 24
12. New Year's Day Observance : 星期五, 2021, 12, 31

And here are the 3 public holidays falling on a weekend:

1. Juneteenth : 星期六, 2021, 06, 19
2. Independence Day : 星期日, 2021, 07, 4
3. Christmas : 星期六, 2021, 12, 25