In [1]:

    

import calendar
import datetime


    

In [2]:

    

def get_day_of_nth_dow(year, month, nth, dow):
    '''dow: Monday(0) - Sunday(6)'''
    if nth < 1 or dow < 0 or dow > 6:
        return None
    
    first_dow, n = calendar.monthrange(year, month)
    day = 7 * (nth - 1) + (dow - first_dow) % 7 + 1
    
    return day if day <= n else None


    

In [3]:

    

print(calendar.month(2019, 1))


    

    




    January 2019
Mo Tu We Th Fr Sa Su
    1  2  3  4  5  6
 7  8  9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30 31

In [4]:

    

print(get_day_of_nth_dow(2019, 1, 1, 1))  # 1st Tuesday(1)


    

    




1

In [5]:

    

print(get_day_of_nth_dow(2019, 1, 2, 0))  # 2nd Monday(0)


    

    




14

In [6]:

    

print(get_day_of_nth_dow(2019, 1, 3, 6))  # 3rd Sunday(6)


    

    




20

In [7]:

    

print(get_day_of_nth_dow(2019, 1, 5, 3))  # 5th Thursday(3)


    

    




31

In [8]:

    

print(get_day_of_nth_dow(2019, 1, 5, 4))


    

    




None

In [9]:

    

print(get_day_of_nth_dow(2019, 1, 0, 4))


    

    




None

In [10]:

    

print(get_day_of_nth_dow(2019, 1, 1, 10))


    

    




None

In [11]:

    

print(get_day_of_nth_dow(2019, 1, 2, 1.8))


    

    




8.8

In [12]:

    

def get_date_of_nth_dow(year, month, nth, dow):
    day = get_day_of_nth_dow(year, month, nth, dow)
    return datetime.date(year, month, day) if day else None


    

In [13]:

    

print(get_date_of_nth_dow(2019, 1, 1, 1))


    

    




2019-01-01

In [14]:

    

print(get_date_of_nth_dow(2019, 1, 1, 10))


    

    




None

In [15]:

    

# print(get_date_of_nth_dow(2019, 1, 2, 1.8))
# TypeError: integer argument expected, got float


    

In [16]:

    

print([(m, get_day_of_nth_dow(2019, m, 2, 0)) for m in range(1, 13)])


    

    




[(1, 14), (2, 11), (3, 11), (4, 8), (5, 13), (6, 10), (7, 8), (8, 12), (9, 9), (10, 14), (11, 11), (12, 9)]

In [17]:

    

for y in range(2020, 2030):
    print(get_date_of_nth_dow(y, 1, 2, 0))


    

    




2020-01-13
2021-01-11
2022-01-10
2023-01-09
2024-01-08
2025-01-13
2026-01-12
2027-01-11
2028-01-10
2029-01-08