Python计算指定范围日期的完全指南

from datetime import datetime, timedelta
import calendar

def get_month_range(date=None):
    """获取当月的第一天和最后一天"""
    date = date or datetime.today()
    # 当月第一天
    first_day = date.replace(day=1)
    
    # 当月最后一天
    _, last_day_num = calendar.monthrange(date.year, date.month)
    last_day = date.replace(day=last_day_num)
    
    return first_day, last_day

# 使用示例
start, end = get_month_range()
print(f"当月第一天: {start.strftime('%Y-%m-%d')}")
print(f"当月最后一天: {end.strftime('%Y-%m-%d')}")

def generate_month_dates(date=None):
    """生成当月所有日期列表"""
    start, end = get_month_range(date)
    current = start
    dates = []
    
    while current <= end:
        dates.append(current)
        current += timedelta(days=1)
    
    return dates

# 使用示例
dates = generate_month_dates()
print(f"当月共{len(dates)}天: 从{dates[0].strftime('%m-%d')}到{dates[-1].strftime('%m-%d')}")

import pytz
from dateutil.relativedelta import relativedelta

def get_month_range_tz(timezone='Asia/Shanghai', date=None):
    """时区敏感的当月范围"""
    tz = pytz.timezone(timezone)
    now = datetime.now(tz) if date is None else date.astimezone(tz)
    
    # 当月第一天
    first_day = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
    
    # 当月最后一天
    next_month = first_day + relativedelta(months=1)
    last_day = next_month - timedelta(days=1)
    last_day = last_day.replace(hour=23, minute=59, second=59, microsecond=999999)
    
    return first_day, last_day

# 使用示例
shanghai_start, shanghai_end = get_month_range_tz('Asia/Shanghai')
newyork_start, newyork_end = get_month_range_tz('America/New_York')

print(f"上海当月范围: {shanghai_start} 至 {shanghai_end}")
print(f"纽约当月范围: {newyork_start} 至 {newyork_end}")

class BusinessMonthCalculator:
    """工作日范围计算器"""
    def __init__(self, holidays=None):
        self.holidays = holidays or set()
    
    def add_holiday(self, date):
        """添加节假日"""
        self.holidays.add(date)
    
    def is_business_day(self, date):
        """检查是否为工作日"""
        # 周末检查
        if date.weekday() >= 5:  # 5=周六, 6=周日
            return False
        # 节假日检查
        return date.date() not in self.holidays
    
    def get_business_days(self, month=None):
        """获取当月所有工作日"""
        month = month or datetime.today()
        start, end = get_month_range(month)
        current = start
        business_days = []
        
        while current <= end:
            if self.is_business_day(current):
                business_days.append(current)
            current += timedelta(days=1)
        
        return business_days

# 使用示例
calculator = BusinessMonthCalculator()
# 添加节假日
calculator.add_holiday(datetime(2023, 12, 25).date())  # 圣诞节

business_days = calculator.get_business_days()
print(f"12月工作日天数: {len(business_days)}")

def fiscal_month_range(date=None, fiscal_start_day=26):
    """计算财务月范围（上月26日到本月25日）"""
    date = date or datetime.today()
    
    if date.day >= fiscal_start_day:
        # 本月26日到下月25日
        start = datetime(date.year, date.month, fiscal_start_day)
        end_month = date.month + 1 if date.month < 12 else 1
        end_year = date.year if date.month < 12 else date.year + 1
        end = datetime(end_year, end_month, fiscal_start_day) - timedelta(days=1)
    else:
        # 上月26日到本月25日
        prev_month = date.replace(day=1) - timedelta(days=1)
        start = datetime(prev_month.year, prev_month.month, fiscal_start_day)
        end = datetime(date.year, date.month, fiscal_start_day) - timedelta(days=1)
    
    return start.date(), end.date()

# 使用示例
fiscal_start, fiscal_end = fiscal_month_range()
print(f"财务月范围: {fiscal_start} 至 {fiscal_end}")

def payroll_period(date=None):
    """计算工资结算周期（上月26日到本月25日）"""
    date = date or datetime.today()
    # 结算日为每月25日
    if date.day >= 26:
        # 本月26日到下月25日
        start = datetime(date.year, date.month, 26)
        end_month = date.month + 1 if date.month < 12 else 1
        end_year = date.year if date.month < 12 else date.year + 1
        end = datetime(end_year, end_month, 25)
    else:
        # 上月26日到本月25日
        prev_month = date.replace(day=1) - timedelta(days=1)
        start = datetime(prev_month.year, prev_month.month, 26)
        end = datetime(date.year, date.month, 25)
    
    return start.date(), end.date()

# 使用示例
pay_start, pay_end = payroll_period()
print(f"工资结算周期: {pay_start} 至 {pay_end}")

import pandas as pd

def monthly_aggregation(data, date_col='date', agg_func='sum'):
    """月度数据聚合"""
    # 确保日期为datetime类型
    data[date_col] = pd.to_datetime(data[date_col])
    
    # 添加月份列
    data['month'] = data[date_col].dt.to_period('M')
    
    # 分组聚合
    aggregated = data.groupby('month').agg(agg_func)
    return aggregated

# 使用示例
# 创建测试数据
dates = pd.date_range('2023-01-01', '2023-12-31', freq='D')
values = np.random.rand(len(dates)) * 100
df = pd.DataFrame({'date': dates, 'value': values})

# 月度聚合
monthly_data = monthly_aggregation(df, agg_func={'value': 'mean'})
print("月度平均值:")
print(monthly_data.head())

def user_activity_analysis(activity_data):
    """用户月度活跃度分析"""
    # 复制数据
    df = activity_data.copy()
    
    # 转换日期
    df['date'] = pd.to_datetime(df['timestamp']).dt.date
    
    # 获取当月范围
    current_month_start, current_month_end = get_month_range()
    
    # 筛选当月数据
    mask = (df['date'] >= current_month_start.date()) & (df['date'] <= current_month_end.date())
    current_month_data = df[mask]
    
    # 计算活跃用户
    active_users = current_month_data['user_id'].nunique()
    
    # 计算活跃天数
    active_days = current_month_data.groupby('user_id')['date'].nunique().mean()
    
    # 计算留存率
    if 'first_login' in df.columns:
        new_users = df[df['first_login'].dt.month == current_month_start.month]['user_id'].nunique()
        retained_users = len(set(df[df['first_login'].dt.month == current_month_start.month]['user_id']) &
                            set(current_month_data['user_id']))
        retention_rate = retained_users / new_users if new_users > 0 else 0
    else:
        retention_rate = None
    
    return {
        'active_users': active_users,
        'active_days': active_days,
        'retention_rate': retention_rate
    }

# 使用示例
# 模拟数据
data = {
    'user_id': [1,1,1,2,2,3,3,3,3],
    'timestamp': pd.date_range('2023-12-01', periods=9, freq='3D'),
    'first_login': [pd.Timestamp('2023-11-15')]*3 + [pd.Timestamp('2023-12-01')]*6
}
df = pd.DataFrame(data)

result = user_activity_analysis(df)
print(f"活跃用户: {result['active_users']}")
print(f"平均活跃天数: {result['active_days']:.2f}")
print(f"留存率: {result['retention_rate']:.2%}")

class SubscriptionSystem:
    """订阅服务计费系统"""
    def __init__(self):
        self.subscriptions = {}
    
    def add_subscription(self, user_id, start_date, billing_cycle='monthly'):
        """添加订阅"""
        self.subscriptions[user_id] = {
            'start_date': start_date,
            'billing_cycle': billing_cycle,
            'next_billing_date': self._calculate_next_billing(start_date, billing_cycle)
        }
    
    def _calculate_next_billing(self, start_date, cycle):
        """计算下次计费日期"""
        if cycle == 'monthly':
            return (start_date + relativedelta(months=1)).replace(day=start_date.day)
        elif cycle == 'quarterly':
            return (start_date + relativedelta(months=3)).replace(day=start_date.day)
        elif cycle == 'yearly':
            return (start_date + relativedelta(years=1)).replace(day=start_date.day)
        else:
            raise ValueError("不支持的计费周期")
    
    def generate_monthly_invoices(self):
        """生成当月账单"""
        current_month_start, current_month_end = get_month_range()
        invoices = []
        
        for user_id, sub in self.subscriptions.items():
            # 检查是否在计费周期内
            if current_month_start <= sub['next_billing_date'] <= current_month_end:
                invoices.append({
                    'user_id': user_id,
                    'amount': 100,  # 示例金额
                    'billing_date': sub['next_billing_date']
                })
                # 更新下次计费日期
                sub['next_billing_date'] = self._calculate_next_billing(
                    sub['next_billing_date'], sub['billing_cycle']
                )
        
        return invoices

# 使用示例
system = SubscriptionSystem()
system.add_subscription('user1', datetime(2023, 11, 15), 'monthly')
system.add_subscription('user2', datetime(2023, 12, 10), 'monthly')

# 生成12月账单
invoices = system.generate_monthly_invoices()
print(f"12月账单数量: {len(invoices)}")

def calculate_trial_period(start_date, trial_days=14):
    """计算试用期结束日期"""
    from pandas.tseries.offsets import BDay
    
    # 工作日计算
    end_date = start_date + trial_days * BDay()
    
    # 确保在当月范围内
    month_start, month_end = get_month_range(start_date)
    if end_date > month_end:
        end_date = month_end
    
    return end_date

# 使用示例
signup_date = datetime(2023, 12, 20)
trial_end = calculate_trial_period(signup_date)
print(f"试用期结束: {trial_end.strftime('%Y-%m-%d')}")

def monthly_project_plan(project_start, project_end):
    """生成项目月度计划"""
    current = project_start.replace(day=1)
    plan = []
    
    while current <= project_end:
        # 获取当月范围
        month_start = current.replace(day=1)
        _, last_day = calendar.monthrange(current.year, current.month)
        month_end = current.replace(day=last_day)
        
        # 调整项目边界
        if month_start < project_start:
            month_start = project_start
        if month_end > project_end:
            month_end = project_end
        
        plan.append({
            'month': current.strftime('%Y-%m'),
            'start': month_start.date(),
            'end': month_end.date(),
            'duration': (month_end - month_start).days + 1
        })
        
        # 下个月
        current = (current.replace(day=1) + relativedelta(months=1))
    
    return plan

# 使用示例
project_start = datetime(2023, 11, 15)
project_end = datetime(2024, 2, 10)
plan = monthly_project_plan(project_start, project_end)

print("项目月度计划:")
for p in plan:
    print(f"{p['month']}: {p['start']} 至 {p['end']} ({p['duration']}天)")

def monthly_resource_allocation(resources, start_date, end_date):
    """资源月度分配计划"""
    # 生成月度范围
    months = []
    current = start_date.replace(day=1)
    while current <= end_date:
        months.append(current.strftime('%Y-%m'))
        current += relativedelta(months=1)
    
    # 初始化分配表
    allocation = pd.DataFrame(index=resources, columns=months)
    
    # 计算每个资源每月分配天数
    for resource in resources:
        current = start_date
        while current <= end_date:
            month = current.strftime('%Y-%m')
            # 计算当月天数
            if current.month == start_date.month and current.year == start_date.year:
                # 首月
                month_start = start_date
                _, last_day = calendar.monthrange(current.year, current.month)
                month_end = current.replace(day=last_day)
            elif current.month == end_date.month and current.year == end_date.year:
                # 末月
                month_start = current.replace(day=1)
                month_end = end_date
            else:
                # 完整月
                month_start = current.replace(day=1)
                _, last_day = calendar.monthrange(current.year, current.month)
                month_end = current.replace(day=last_day)
            
            # 计算工作天数
            days = (month_end - month_start).days + 1
            allocation.loc[resource, month] = days
            
            # 下个月
            current = (current.replace(day=1) + relativedelta(months=1))
    
    return allocation

# 使用示例
resources = ['开发团队', '测试团队', '设计团队']
start_date = datetime(2023, 12, 10)
end_date = datetime(2024, 2, 20)

allocation = monthly_resource_allocation(resources, start_date, end_date)
print("资源月度分配表:")
print(allocation)

import numpy as np

def batch_month_ranges(dates):
    """批量计算日期所在月份范围"""
    # 转换为datetime数组
    dates = np.array(dates, dtype='datetime64')
    
    # 计算当月第一天
    first_days = dates.astype('datetime64[M]')
    
    # 计算当月最后一天
    next_months = first_days + np.timedelta64(1, 'M')
    last_days = next_months - np.timedelta64(1, 'D')
    
    return first_days, last_days

# 使用示例
test_dates = [
    '2023-01-15', '2023-02-28', '2023-12-01',
    '2024-01-01', '2024-02-29'  # 闰年测试
]

first_days, last_days = batch_month_ranges(test_dates)
for i, date in enumerate(test_dates):
    print(f"{date} 所在月份: {first_days[i]} 至 {last_days[i]}")

def efficient_month_dates(year, month):
    """高效生成当月所有日期"""
    # 计算当月天数
    _, num_days = calendar.monthrange(year, month)
    
    # 生成日期范围
    start = datetime(year, month, 1)
    dates = [start + timedelta(days=i) for i in range(num_days)]
    
    return dates

# 性能对比
%timeit generate_month_dates(datetime(2023, 12, 1))  # 传统方法
%timeit efficient_month_dates(2023, 12)  # 高效方法

# 所有操作前转换为UTC
utc_time = datetime.now(pytz.utc)
# 操作后转换回本地时间
local_time = utc_time.astimezone(pytz.timezone('Asia/Shanghai'))

# 安全获取月末
def safe_month_end(year, month):
    try:
        return datetime(year, month, 31)
    except ValueError:
        try:
            return datetime(year, month, 30)
        except ValueError:
            return datetime(year, month, 28)  # 闰年处理在monthrange中

# 批量处理使用numpy
dates = np.array(['2023-01-01', '2023-02-01'], dtype='datetime64')
month_starts = dates.astype('datetime64[M]')

def get_month_range_safe(date=None):
    try:
        return get_month_range(date)
    except ValueError as e:
        # 处理无效日期
        print(f"日期错误: {str(e)}")
        return None, None
    except TypeError:
        # 处理类型错误
        print("无效日期类型")
        return None, None

def is_leap_year(year):
    """检查闰年"""
    return year % 4 == 0 and (year % 100 != 0 or year % 400 == 0)

def february_days(year):
    """获取二月天数"""
    return 29 if is_leap_year(year) else 28

def get_month_range(date=None):
    """
    获取当月的第一天和最后一天

    参数:
        date: 基准日期 (默认今天)

    返回:
        (first_day, last_day) 当月第一天和最后一天的datetime对象

    示例:
        >>> get_month_range(datetime(2023, 12, 15))
        (datetime(2023, 12, 1), datetime(2023, 12, 31))
    """
    # 实现代码