Python timedelta详解 - 时间间隔运算与日期计算技巧

from datetime import timedelta

# 完整构造函数
td = timedelta(days=0, seconds=0, microseconds=0,
               milliseconds=0, minutes=0, hours=0, weeks=0)

# 常用创建方式
td1 = timedelta(days=7)                  # 7天
td2 = timedelta(hours=2, minutes=30)     # 2小时30分钟
td3 = timedelta(weeks=1, days=2, hours=3) # 1周2天3小时

from datetime import timedelta

# 不同方式创建
td1 = timedelta(days=7)
td2 = timedelta(hours=2, minutes=30)
td3 = timedelta(weeks=1, days=2, hours=3)

print(f"一周: {td1}")
print(f"2小时30分: {td2}")
print(f"1周2天3小时: {td3}")

# 访问属性
print(f"\ntd3.days: {td3.days}")
print(f"td3.seconds: {td3.seconds}")
print(f"td3.total_seconds(): {td3.total_seconds()}")

# 负数时间间隔
td_neg = timedelta(days=-3)
print(f"\n负3天: {td_neg}")
print(f"总秒数: {td_neg.total_seconds()}")

一周: 7 days, 0:00:00
2小时30分: 2:30:00
1周2天3小时: 9 days, 3:00:00

td3.days: 9
td3.seconds: 10800
td3.total_seconds(): 790800.0

负3天: -3 days, 0:00:00
总秒数: -259200.0

from datetime import datetime, timedelta

now = datetime(2024, 1, 15, 10, 30, 0)

# 日期时间加减
print(f"当前: {now}")
print(f"1小时后: {now + timedelta(hours=1)}")
print(f"3天前: {now - timedelta(days=3)}")
print(f"2周后: {now + timedelta(weeks=2)}")

当前: 2024-01-15 10:30:00
1小时后: 2024-01-15 11:30:00
3天前: 2024-01-12 10:30:00
2周后: 2024-01-29 10:30:00

from datetime import date, datetime, timedelta

# date 与 timedelta 运算
d1 = date(2024, 1, 15)
d2 = d1 + timedelta(days=10)
print(f"d2 = {d2}")  # 2024-01-25

# 两个 datetime 相减得到 timedelta
dt1 = datetime(2024, 1, 15, 10, 30)
dt2 = datetime(2024, 1, 10, 8, 0)
diff = dt1 - dt2
print(f"差值: {diff}")           # 5 days, 2:30:00
print(f"差值天数: {diff.days}")    # 5
print(f"差值秒数: {diff.seconds}") # 9000
print(f"总秒数: {diff.total_seconds()}") # 439800.0

from datetime import timedelta

td1 = timedelta(days=5, hours=3)
td2 = timedelta(days=2, hours=6)

# timedelta 加减
print(f"td1 + td2 = {td1 + td2}")  # 7 days, 9:00:00
print(f"td1 - td2 = {td1 - td2}")  # 2 days, 21:00:00

# timedelta 乘除（整数）
print(f"td1 * 2 = {td1 * 2}")      # 10 days, 6:00:00
print(f"td1 / 2 = {td1 / 2}")      # 2 days, 13:30:00

# timedelta 比较
print(f"\ntd1 > td2: {td1 > td2}")  # True
print(f"td1 == timedelta(days=5, hours=3): {td1 == timedelta(days=5, hours=3)}")  # True

from datetime import datetime, timedelta

class ProjectTracker:
    """项目进度跟踪器"""

    def __init__(self, name, start_date, duration_days):
        self.name = name
        self.start = start_date
        self.duration = timedelta(days=duration_days)
        self.end = self.start + self.duration

    def progress(self, current_date=None):
        """计算项目进度百分比"""
        if current_date is None:
            current_date = datetime.now()

        if current_date <= self.start:
            return 0.0
        elif current_date >= self.end:
            return 100.0
        else:
            elapsed = current_date - self.start
            return (elapsed / self.duration) * 100

    def remaining(self, current_date=None):
        """计算剩余时间"""
        if current_date is None:
            current_date = datetime.now()

        if current_date >= self.end:
            return timedelta(0)
        return self.end - current_date

    def summary(self, current_date=None):
        """输出项目摘要"""
        if current_date is None:
            current_date = datetime.now()

        pct = self.progress(current_date)
        rem = self.remaining(current_date)
        status = "已完成" if pct >= 100 else "进行中" if pct > 0 else "未开始"

        print(f"项目: {self.name}")
        print(f"  开始: {self.start.strftime('%Y-%m-%d')}")
        print(f"  结束: {self.end.strftime('%Y-%m-%d')}")
        print(f"  工期: {self.duration.days} 天")
        print(f"  进度: {pct:.1f}%")
        print(f"  剩余: {rem.days} 天")
        print(f"  状态: {status}")

# 使用示例
start = datetime(2024, 1, 1)
tracker = ProjectTracker("网站重构", start, 90)
current = datetime(2024, 2, 15)
tracker.summary(current)

项目: 网站重构
  开始: 2024-01-01
  结束: 2024-03-31
  工期: 90 天
  进度: 50.0%
  剩余: 45 天
  状态: 进行中