zellers_congruence.py

importargparse
importdatetime


defzeller(date_input: str) ->str:
"""
 | Zellers Congruence Algorithm
 | Find the day of the week for nearly any Gregorian or Julian calendar date

 >>> zeller('01-31-2010')
 'Your date 01-31-2010, is a Sunday!'

 Validate out of range month:

 >>> zeller('13-31-2010')
 Traceback (most recent call last):
 ...
 ValueError: Month must be between 1 - 12
 >>> zeller('.2-31-2010')
 Traceback (most recent call last):
 ...
 ValueError: invalid literal for int() with base 10: '.2'

 Validate out of range date:

 >>> zeller('01-33-2010')
 Traceback (most recent call last):
 ...
 ValueError: Date must be between 1 - 31
 >>> zeller('01-.4-2010')
 Traceback (most recent call last):
 ...
 ValueError: invalid literal for int() with base 10: '.4'

 Validate second separator:

 >>> zeller('01-31*2010')
 Traceback (most recent call last):
 ...
 ValueError: Date separator must be '-' or '/'

 Validate first separator:

 >>> zeller('01^31-2010')
 Traceback (most recent call last):
 ...
 ValueError: Date separator must be '-' or '/'

 Validate out of range year:

 >>> zeller('01-31-8999')
 Traceback (most recent call last):
 ...
 ValueError: Year out of range. There has to be some sort of limit...right?

 Test null input:

 >>> zeller()
 Traceback (most recent call last):
 ...
 TypeError: zeller() missing 1 required positional argument: 'date_input'

 Test length of `date_input`:

 >>> zeller('')
 Traceback (most recent call last):
 ...
 ValueError: Must be 10 characters long
 >>> zeller('01-31-19082939')
 Traceback (most recent call last):
 ...
 ValueError: Must be 10 characters long"""

# Days of the week for response
days= {
"0": "Sunday",
"1": "Monday",
"2": "Tuesday",
"3": "Wednesday",
"4": "Thursday",
"5": "Friday",
"6": "Saturday",
 }

convert_datetime_days= {0: 1, 1: 2, 2: 3, 3: 4, 4: 5, 5: 6, 6: 0}

# Validate
ifnot0<len(date_input) <11:
raiseValueError("Must be 10 characters long")

# Get month
m: int=int(date_input[0] +date_input[1])
# Validate
ifnot0<m<13:
raiseValueError("Month must be between 1 - 12")

sep_1: str=date_input[2]
# Validate
ifsep_1notin ["-", "/"]:
raiseValueError("Date separator must be '-' or '/'")

# Get day
d: int=int(date_input[3] +date_input[4])
# Validate
ifnot0<d<32:
raiseValueError("Date must be between 1 - 31")

# Get second separator
sep_2: str=date_input[5]
# Validate
ifsep_2notin ["-", "/"]:
raiseValueError("Date separator must be '-' or '/'")

# Get year
y: int=int(date_input[6] +date_input[7] +date_input[8] +date_input[9])
# Arbitrary year range
ifnot45<y<8500:
raiseValueError(
"Year out of range. There has to be some sort of limit...right?"
 )

# Get datetime obj for validation
dt_ck=datetime.date(int(y), int(m), int(d))

# Start math
ifm<=2:
y=y-1
m=m+12
# maths var
c: int=int(str(y)[:2])
k: int=int(str(y)[2:])
t: int=int(2.6*m-5.39)
u: int=int(c/4)
v: int=int(k/4)
x: int=int(d+k)
z: int=int(t+u+v+x)
w: int=int(z- (2*c))
f: int=round(w%7)
# End math

# Validate math
iff!=convert_datetime_days[dt_ck.weekday()]:
raiseAssertionError("The date was evaluated incorrectly. Contact developer.")

# Response
response: str=f"Your date {date_input}, is a {days[str(f)]}!"
returnresponse


if__name__=="__main__":
importdoctest

doctest.testmod()
parser=argparse.ArgumentParser(
description=(
"Find out what day of the week nearly any date is or was. Enter "
"date as a string in the mm-dd-yyyy or mm/dd/yyyy format"
 )
 )
parser.add_argument(
"date_input", type=str, help="Date as a string (mm-dd-yyyy or mm/dd/yyyy)"
 )
args=parser.parse_args()
zeller(args.date_input)