Python datetime: 20 Common Date and Time Operations with Code Examples

1. Get the current date and time:

from datetime import datetime

now = datetime.now()

print("当前时间:", now)

2. Format and print the current time:

formatted_time = datetime.now().strftime("%Y-%m-%d %H:%M:%S")

print("格式化后的当前时间:", formatted_time)

3. Calculate the difference in days between two dates:

from datetime import datetime

date1 = datetime(2025, 5, 1)

date2 = datetime(2025, 6, 1)

difference = (date2 - date1).days

print(f"{date1} 和 {date2} 之间相差 {difference} 天")

4. Convert a string to a datetime object:

from datetime import datetime

date_str = "2025-05-01"

date_obj = datetime.strptime(date_str, "%Y-%m-%d")

print("日期对象:", date_obj)

5. Convert a datetime object to a string:

from datetime import datetime

date_obj = datetime.now()

date_str = date_obj.strftime("%Y-%m-%d")

print("日期字符串:", date_str)

6. Get today's date:

from datetime import date

today = date.today()

print("今天的日期:", today)

7. Add one day to the current date:

from datetime import datetime, timedelta

now = datetime.now()

tomorrow = now + timedelta(days=1)

print("明天的日期:", tomorrow)

8. Subtract one hour from the current time:

from datetime import datetime, timedelta

an_hour_ago = datetime.now() - timedelta(hours=1)

print("一小时前的时间:", an_hour_ago)

9. Determine if a year is a leap year:

import calendar

year = 2024

if calendar.isleap(year):

print(f"{year} 是闰年")

else:

print(f"{year} 不是闰年")

10. Get the first and last day of the current month:

from datetime import datetime, timedelta

first_day = datetime.today().replace(day=1)

last_day = (first_day + timedelta(days=32)).replace(day=1) - timedelta(days=1)

print("本月第一天:", first_day.date())

print("本月最后一天:", last_day.date())

11. Create a simple countdown timer:

import time

def countdown(t):

while t:

mins, secs = divmod(t, 60)

timer = '{:02d}:{:02d}'.format(mins, secs)

print(timer, end="\r")

time.sleep(1)

t -= 1

countdown(5)

print("计时结束")

12. Schedule a task using the sched module:

import sched, time

scheduler = sched.scheduler(time.time, time.sleep)

def print_event(name):

print(f"事件: {name} 在 {time.time()} 执行")

print('开始:', time.time())

scheduler.enter(2, 1, print_event, ('事件1',))

scheduler.run()

13. Print the calendar for a specific month:

import calendar

year = 2025

month = 5

print(calendar.month(year, month))

14. Convert a timestamp to a datetime:

import time

from datetime import datetime

timestamp = time.time()

print("时间戳:", timestamp)

date_time = datetime.fromtimestamp(timestamp)

print("日期时间:", date_time)

15. Convert a datetime string to a timestamp:

from datetime import datetime

date_time_str = '2025-05-05 12:00:00'

date_time_obj = datetime.strptime(date_time_str, '%Y-%m-%d %H:%M:%S')

timestamp = date_time_obj.timestamp()

print("时间戳:", timestamp)

16. Determine the weekday of a given date:

from datetime import datetime

date = datetime(2025, 5, 5)

print(date.strftime("%A"))  # 输出星期几

17. Calculate a date after adding a number of working days (excluding weekends):

from datetime import datetime, timedelta

def add_working_days(start_date, days):

current_date = start_date

added_days = 0

while added_days < days:

current_date += timedelta(days=1)

if current_date.weekday() < 5:  # 排除周末

added_days += 1

return current_date

start_date = datetime(2025, 5, 5)

print(add_working_days(start_date, 10))  # 10个工作日后的日期

18. Compute the number of weeks between two dates:

from datetime import datetime

date1 = datetime(2025, 5, 1)

date2 = datetime(2025, 6, 1)

weeks_difference = (date2 - date1).days // 7

print(f"{date1} 和 {date2} 之间相差 {weeks_difference} 周")

19. Get the Monday and Sunday of the current week:

from datetime import datetime, timedelta

today = datetime.today()

start_of_week = today - timedelta(days=today.weekday())

end_of_week = start_of_week + timedelta(days=6)

print("本周周一:", start_of_week.date())

print("本周周日:", end_of_week.date())

20. Introduce a simple delay using time.sleep() :

import time

print("开始")

time.sleep(2)  # 等待2秒

print("2秒后...")