Print all day-dates between two dates

Step-by-step to printing all day-dates

There's no such thing as too much date handling. Let's dissect the script, piece by piece, to fully grasp the concept:

Step 1: Initialization (Bringing the date to the party)

from datetime import datetime

start_date = datetime.strptime('2023-01-01', '%Y-%m-%d')
end_date = datetime.strptime('2023-01-31', '%Y-%m-%d')
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Step 2: Picture a day (Or don't. We're just adding one to the current date)

from datetime import timedelta

# Creating a day interval - treadmills for dates
one_day = timedelta(days=1)
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Step 3: Generator—Our own date yielder

def date_generator(start, end, step):
    while start <= end:              # 'cause we don't like overshooting
        yield start                  # Hands out date on a silver platter
        start += step                # Next date, please!
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Generators are more memory-friendly, particularly over large ranges.

Step 4: Print it out (Or do some magic)

for single_date in date_generator(start_date, end_date, one_day):
    print(single_date.date().isoformat())    # ISO formatting because we aren't animals.
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Note: Sit back and watch as .isoformat() transforms your output into a MMP (Machine and Man-friendly Print).

Create a list of all dates (Meet the List Comprehensions Squad)

Wondering how to skim all dates into a list? List comprehensions are here to save the day:

dates_list = [start_date + timedelta(days=n) for n in range((end_date - start_date).days + 1)]
print([date.isoformat() for date in dates_list])    # Lock, Load and Print!
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Compact, efficient and considerate towards the end date.

Fine-tuning for edge cases

Robust solutions factor in weirdness. Let's deal with some potential pain points.

Leap years and timezone-aware dates

Leap years and timezones can play spoilsport.

# Hey, it's Leap Year Detection Squad
import calendar

year = 2024  # A wild leap year appears
print(calendar.isleap(year))  # Outputs: True

# Timezone aware start and end dates
from datetime import timezone
import pytz

start_date = start_date.replace(tzinfo=pytz.UTC)
end_date = end_date.replace(tzinfo=timezone.utc)  # UTC for consistency
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New Year's rollover

The algorithm shan't be puzzled if dates span multiple years.

start_date = datetime.strptime('2022-12-31', '%Y-%m-%d')
end_date = datetime.strptime('2023-01-02', '%Y-%m-%d')  # We party on New Year’s Eve!
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