Python datetime日期时间处理

from datetime import datetime

# 获取当前日期和时间
now = datetime.now()
print("当前时间:", now)

# 分别获取日期部分和时间部分
print("日期:", now.date())
print("时间:", now.time())
print("年份:", now.year)
print("月份:", now.month)
print("日期:", now.day)
print("小时:", now.hour)
print("分钟:", now.minute)
print("秒:", now.second)

from datetime import datetime, date, time

# 创建完整的日期时间对象
new_year = datetime(2024, 1, 1, 0, 0, 0)
print("2024年元旦:", new_year)

# 只创建日期
birthday = date(1990, 5, 15)
print("生日日期:", birthday)

# 只创建时间
meeting_time = time(14, 30, 0)
print("会议时间:", meeting_time)

from datetime import datetime

now = datetime.now()

# 常用格式化方式
print("默认格式:", now)
print("ISO格式:", now.isoformat())
print("年月日:", now.strftime("%Y-%m-%d"))
print("中文格式:", now.strftime("%Y年%m月%d日"))
print("详细时间:", now.strftime("%H时%M分%S秒"))
print("完整格式:", now.strftime("%Y-%m-%d %H:%M:%S"))
print("星期:", now.strftime("%A"))  # 英文星期
print("简写星期:", now.strftime("%a"))  # 英文星期简写

from datetime import datetime

# 从字符串解析日期时间
date_str = "2024-01-20 15:30:00"
dt = datetime.strptime(date_str, "%Y-%m-%d %H:%M:%S")
print("解析结果:", dt)

# 解析不同格式的日期
formats = [
    ("20/01/2024", "%d/%m/%Y"),
    ("2024年1月20日", "%Y年%m月%d日"),
    ("Jan 20, 2024", "%b %d, %Y")
]

for date_str, format_str in formats:
    dt = datetime.strptime(date_str, format_str)
    print(f"{date_str} -> {dt}")

from datetime import datetime, timedelta

# 当前时间
now = datetime.now()
print("现在:", now)

# 计算未来时间
one_week_later = now + timedelta(days=7)
three_hours_later = now + timedelta(hours=3)
print("一周后:", one_week_later)
print("三小时后:", three_hours_later)

# 计算过去时间
yesterday = now - timedelta(days=1)
two_weeks_ago = now - timedelta(weeks=2)
print("昨天:", yesterday)
print("两周前:", two_weeks_ago)

# 复杂时间计算
future = now + timedelta(
    days=5,
    hours=3,
    minutes=30,
    seconds=45
)
print("5天3小时30分45秒后:", future)

from datetime import datetime, date

# 创建几个日期进行比较
date1 = date(2024, 1, 15)
date2 = date(2024, 1, 20)
date3 = date(2024, 1, 25)

print(f"日期1: {date1}")
print(f"日期2: {date2}")
print(f"日期3: {date3}")

# 比较操作
print(f"日期1 < 日期2: {date1 < date2}")
print(f"日期2 > 日期3: {date2 > date3}")
print(f"日期1 == 日期2: {date1 == date2}")

# 计算日期差
date_diff = date2 - date1
print(f"日期2和日期1相差: {date_diff.days} 天")

from datetime import date, timedelta

def calculate_age(birth_date):
    """计算年龄"""
    today = date.today()
    age = today.year - birth_date.year
    
    # 如果今年生日还没过，年龄减1
    if today < date(today.year, birth_date.month, birth_date.day):
        age -= 1
    
    return age

def days_until_birthday(birth_date):
    """计算距离下次生日的天数"""
    today = date.today()
    next_birthday = date(today.year, birth_date.month, birth_date.day)
    
    # 如果今年生日已经过了，计算明年的生日
    if today > next_birthday:
        next_birthday = date(today.year + 1, birth_date.month, birth_date.day)
    
    days_left = (next_birthday - today).days
    return days_left

# 测试生日计算
birthday = date(1990, 5, 15)
age = calculate_age(birthday)
days_left = days_until_birthday(birthday)

print(f"出生日期: {birthday}")
print(f"当前年龄: {age}岁")
print(f"距离下次生日还有: {days_left}天")

from datetime import date, timedelta

def calculate_workdays(start_date, end_date):
    """计算两个日期之间的工作日数量（排除周末）"""
    workdays = 0
    current_date = start_date
    
    while current_date <= end_date:
        # 周一至周五是工作日
        if current_date.weekday() < 5:  # 0=周一, 4=周五
            workdays += 1
        current_date += timedelta(days=1)
    
    return workdays

def add_workdays(start_date, workdays_to_add):
    """在起始日期上添加指定工作日"""
    current_date = start_date
    workdays_added = 0
    
    while workdays_added < workdays_to_add:
        current_date += timedelta(days=1)
        if current_date.weekday() < 5:  # 工作日
            workdays_added += 1
    
    return current_date

# 测试工作日计算
start = date(2024, 1, 15)  # 周一
end = date(2024, 1, 25)    # 周四

total_workdays = calculate_workdays(start, end)
print(f"从 {start} 到 {end} 的工作日数量: {total_workdays}")

# 添加10个工作日
new_date = add_workdays(start, 10)
print(f"{start} 加上10个工作日是: {new_date}")

from datetime import datetime

# 获取当前时间戳
current_timestamp = datetime.now().timestamp()
print(f"当前时间戳: {current_timestamp}")

# 时间戳转日期时间
timestamp = 1705734000  # 2024年1月20日 12:00:00
dt_from_timestamp = datetime.fromtimestamp(timestamp)
print(f"时间戳 {timestamp} 对应的日期时间: {dt_from_timestamp}")

# 日期时间转时间戳
dt = datetime(2024, 1, 20, 12, 0, 0)
timestamp_from_dt = dt.timestamp()
print(f"日期时间 {dt} 对应的时间戳: {timestamp_from_timestamp}")

from datetime import datetime
import time

def measure_execution_time(func):
    """测量函数执行时间"""
    start_time = datetime.now()
    
    # 执行函数
    func()
    
    end_time = datetime.now()
    execution_time = end_time - start_time
    
    print(f"函数执行时间: {execution_time}")
    return execution_time

# 测试函数
def slow_function():
    """模拟耗时操作"""
    time.sleep(2)  # 休眠2秒

# 测量执行时间
execution_time = measure_execution_time(slow_function)
print(f"总秒数: {execution_time.total_seconds():.2f}秒")

from datetime import datetime

def is_valid_date(year, month, day):
    """检查日期是否有效"""
    try:
        datetime(year, month, day)
        return True
    except ValueError:
        return False

def is_valid_time(hour, minute, second):
    """检查时间是否有效"""
    try:
        datetime(2000, 1, 1, hour, minute, second)  # 使用任意有效日期
        return True
    except ValueError:
        return False

# 测试日期时间验证
test_dates = [
    (2024, 2, 29),   # 闰年，有效
    (2023, 2, 29),   # 非闰年，无效
    (2024, 13, 1),   # 无效月份
    (2024, 1, 32),   # 无效日期
]

for year, month, day in test_dates:
    valid = is_valid_date(year, month, day)
    print(f"{year}-{month:02d}-{day:02d}: {'有效' if valid else '无效'}")

# 测试时间验证
test_times = [
    (23, 59, 59),   # 有效
    (24, 0, 0),     # 无效
    (12, 60, 0),    # 无效
]

for hour, minute, second in test_times:
    valid = is_valid_time(hour, minute, second)
    print(f"{hour:02d}:{minute:02d}:{second:02d}: {'有效' if valid else '无效'}")

from datetime import datetime, timezone, timedelta

# 创建时区对象
beijing_tz = timezone(timedelta(hours=8))  # 北京时间 UTC+8
newyork_tz = timezone(timedelta(hours=-5)) # 纽约时间 UTC-5

# 带时区的当前时间
utc_now = datetime.now(timezone.utc)
beijing_now = datetime.now(beijing_tz)

print(f"UTC时间: {utc_now}")
print(f"北京时间: {beijing_now}")

# 时区转换
utc_time = datetime(2024, 1, 20, 12, 0, 0, tzinfo=timezone.utc)
beijing_time = utc_time.astimezone(beijing_tz)
newyork_time = utc_time.astimezone(newyork_tz)

print(f"UTC时间: {utc_time}")
print(f"北京时间: {beijing_time}")
print(f"纽约时间: {newyork_time}")

from datetime import date, timedelta

def generate_date_range(start_date, end_date):
    """生成日期范围内的所有日期"""
    current_date = start_date
    dates = []
    
    while current_date <= end_date:
        dates.append(current_date)
        current_date += timedelta(days=1)
    
    return dates

def get_week_dates(target_date):
    """获取目标日期所在周的所有日期"""
    # 找到周一的日期
    start_of_week = target_date - timedelta(days=target_date.weekday())
    
    # 生成一周的日期
    week_dates = []
    for i in range(7):
        week_dates.append(start_of_week + timedelta(days=i))
    
    return week_dates

# 测试日期范围
start = date(2024, 1, 1)
end = date(2024, 1, 7)
date_range = generate_date_range(start, end)

print("2024年第一周的日期:")
for d in date_range:
    print(f"  {d} ({d.strftime('%A')})")

# 测试获取周日期
today = date.today()
this_week = get_week_dates(today)
print(f"\n本周日期:")
for d in this_week:
    day_name = "周一" if d.weekday() == 0 else \
               "周二" if d.weekday() == 1 else \
               "周三" if d.weekday() == 2 else \
               "周四" if d.weekday() == 3 else \
               "周五" if d.weekday() == 4 else \
               "周六" if d.weekday() == 5 else "周日"
    print(f"  {d} ({day_name})")

from datetime import datetime

class DateFormatter:
    """日期格式化工具类"""
    
    @staticmethod
    def format_chinese(dt):
        """中文格式"""
        return dt.strftime("%Y年%m月%d日 %H时%M分%S秒")
    
    @staticmethod
    def format_iso(dt):
        """ISO格式"""
        return dt.isoformat()
    
    @staticmethod
    def format_readable(dt):
        """易读格式"""
        return dt.strftime("%A, %B %d, %Y at %I:%M %p")
    
    @staticmethod
    def format_filename(dt):
        """文件名格式"""
        return dt.strftime("%Y%m%d_%H%M%S")
    
    @staticmethod
    def format_database(dt):
        """数据库格式"""
        return dt.strftime("%Y-%m-%d %H:%M:%S")

# 使用格式化工具
now = datetime.now()

formatter = DateFormatter()
print("中文格式:", formatter.format_chinese(now))
print("ISO格式:", formatter.format_iso(now))
print("易读格式:", formatter.format_readable(now))
print("文件名格式:", formatter.format_filename(now))
print("数据库格式:", formatter.format_database(now))