Python实现日期判断和加减操作详解

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#时间相关
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def if_workday(day_str, separator=""):
    """
    if a day is workday
    
    :param day_str: string of a day
    :param separator: separator of year, month and day, default is empty
    :return: True: is workday; False: not workday
    """
    spec = "%Y" + separator + "%m" + separator + "%d"
    day = datetime.strptime(day_str, spec).date()
    # Monday == 0 ... Sunday == 6
    if day.weekday() in [0, 1, 2, 3, 4]:
        return True
    else:
        return False
 
def if_weekend(day_str, separator=""):
    """
    if a day is weekend
    
    :param day_str: string of a day
    :param separator: separator of year, month and day, default is empty
    :return: True: is weekend; False: not weekend
    """
    spec = "%Y" + separator + "%m" + separator + "%d"
    day = datetime.strptime(day_str, spec).date()
    # Monday == 0 ... Sunday == 6
    if day.weekday() in [5, 6]:
        return True
    else:
        return False
 
def is_week_lastday():
    '''
    判断今天是否为周末，return the day of the week as an integer,Monday is 0 and Sunday is 6
    
    :return:
    '''
    
    now = (datetime.datetime.utcnow() + datetime.timedelta(hours=8))
    # 假如今天是周日
    todayIndex = now.weekday()
    # 如果今天是周日，则返回True
    if todayIndex == 6:
        print("todayIndex={},今天是周末...".fORMat(todayIndex))
        return True
    else:
        print("todayIndex={},今天是周 {}，不是周末...".format(todayIndex,int(todayIndex+1)))
        return False
    
def is_week_whichday(dayIndex=6):
    '''
    判断今天一周的哪一天，周一为0，周末为6，return the day of the week as an integer,Monday is 0 and Sunday is 6
    
    :return:
    '''
    
    now = (datetime.datetime.utcnow() + datetime.timedelta(hours=8))
    # 假如今天是周日
    todayIndex = now.weekday()
    # 如果今天是周日，则返回True
    if todayIndex == dayIndex:
        print("todayIndex={},今天是周 {}，不是周 {}...".format(todayIndex, int(todayIndex+1),int(dayIndex+1)))
        return True
    else:
        print("todayIndex={},今天是周 {}，不是周 {}...".format(todayIndex,int(todayIndex+1),int(dayIndex+1)))
        return False
 
def is_month_lastday():
    '''
    # 判断今天是否为月末
    
    :return:
    '''
    
    # 获得当月1号的日期
    start_date = datetime.date.today().replace(day=1)
    # 获得当月一共有多少天（也就是最后一天的日期）
    _, days_in_month = calendar.monthrange(start_date.year, start_date.month)
 
    todayIndex = time.strftime("%d", time.localtime())
    
    # 如果今天是周末，返回True
    if int(todayIndex) == int(days_in_month):
        print("start_date={},todayIndex={},days_in_month={},今天是月末...".format(start_date,todayIndex, days_in_month))
        return True
    else:
        print("start_date={},todayIndex={},days_in_month={},今天不是月末...".format(start_date,todayIndex , days_in_month))
        return False
 
def get_this_week_start():
    '''
    获取本周第一天日期
    
    :return:
    '''
    now = datetime.datetime.now()
    this_week_start = now - timedelta(days=now.weekday())
    this_week_end = now + timedelta(days=6 - now.weekday())
    print('--- this_week_start = {} this_week_end = {}'.format(this_week_start, this_week_end))
    print('--- this_week_start = {} '.format(this_week_start))
    return this_week_start
    
def get_this_week_end():
    '''
    # 获取本周最后一天日期
    
    :return:
    '''
    
    now = datetime.datetime.now()
    this_week_start = now - timedelta(days=now.weekday())
    this_week_end = now + timedelta(days=6 - now.weekday())
    print('--- this_week_start = {} this_week_end = {}'.format(this_week_start, this_week_end))
    print('--- this_week_end = {}'.format(this_week_end))
    return this_week_end
 
def get_last_month_start(now = datetime.datetime.now()):
    
    now = datetime.datetime.strptime(now, "%Y-%m-%d")
    # 本月第一天和最后一天
    this_month_start = datetime.datetime(now.year, now.month, 1)
    this_month_end = datetime.datetime(now.year, now.month + 1, 1) - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    # print('--- this_month_start = {} this_month_end = {}'.format(this_month_start, this_month_end))
    
    # 上月第一天和最后一天
    last_month_end = this_month_start - timedelta(days=1)+ datetime.timedelta(hours=23, minutes=59, seconds=59)
    last_month_start = datetime.datetime(last_month_end.year, last_month_end.month, 1)
    # print('--- last_month_end = {} last_month_start = {}'.format(last_month_end, last_month_start))
    print('--- last_month_start = {}'.format(last_month_start))
    return last_month_start
 
def get_last_month_end(now = datetime.datetime.now()):
    now = datetime.datetime.strptime(now, "%Y-%m-%d")
    # 本月第一天和最后一天
    this_month_start = datetime.datetime(now.year, now.month, 1)
    this_month_end = datetime.datetime(now.year, now.month + 1, 1) - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    # print('--- this_month_start = {} this_month_end = {}'.format(this_month_start, this_month_end))
    
    # 上月第一天和最后一天
    last_month_end = this_month_start - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    last_month_start = datetime.datetime(last_month_end.year, last_month_end.month, 1)
    # print('--- last_month_end = {} last_month_start = {}'.format(last_month_end, last_month_start))
    print('--- last_month_end = {} '.format(last_month_end))
    return last_month_end
 
def get_this_month_start(now = datetime.datetime.now()):
    now = datetime.datetime.strptime(now, "%Y-%m-%d")
    # 本月第一天和最后一天
    this_month_start = datetime.datetime(now.year, now.month, 1)
    this_month_end = datetime.datetime(now.year, now.month + 1, 1) - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    # print('--- this_month_start = {} this_month_end = {}'.format(this_month_start, this_month_end))
    
    # 上月第一天和最后一天
    last_month_end = this_month_start - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    last_month_start = datetime.datetime(last_month_end.year, last_month_end.month, 1)
    # print('--- last_month_end = {} last_month_start = {}'.format(last_month_end, last_month_start))
    print('--- this_month_start = {} '.format(this_month_start))
    return this_month_start
 
def get_this_month_end(now = datetime.datetime.now()):
    now=datetime.datetime.strptime(now, "%Y-%m-%d")
    # 本月第一天和最后一天
    this_month_start = datetime.datetime(now.year, now.month, 1)
    # this_month_end = datetime.datetime(now.year, now.month + 1, 1) - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    
    if now.month < 12:
        this_month_end = datetime.datetime(now.year, now.month + 1, 1) - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    elif  now.month >= 12:
        this_month_end = datetime.datetime(now.year, now.month , now.day+30) + datetime.timedelta(hours=23, minutes=59, seconds=59)
 
        
    # print('--- this_month_start = {} this_month_end = {}'.format(this_month_start, this_month_end))
    
    # 上月第一天和最后一天
    last_month_end = this_month_start - timedelta(days=1) + datetime.timedelta(hours=23, minutes=59, seconds=59)
    last_month_start = datetime.datetime(last_month_end.year, last_month_end.month, 1)
    # print('--- last_month_end = {} last_month_start = {}'.format(last_month_end, last_month_start))
    # print('--- this_month_end = {} '.format(this_month_end))
    return str(this_month_end)
 
#从一个时间段获取其中的每一天,可以自定义时间间隔
def get_every_day(start = '2018-01-01',end = '2021-01-01',daysCount=1):
    '''
    从一个时间段获取其中的每一天,可以自定义时间间隔
    
    :param start: str类型，开始时间，如：'2018-01-01'
    :param end: str类型，结束时间，如：'2021-01-01'
    :param daysCount: int类型，每一个时间间隔，默认为1天
    :return:
    '''
    datestart = datetime.datetime.strptime(start, '%Y-%m-%d')
    dateend = datetime.datetime.strptime(end, '%Y-%m-%d')
    
    date_list=[]
    while datestart < dateend:
        datestart += datetime.timedelta(days=daysCount)
        date_str=str(datestart.strftime('%Y-%m-%d'))
        # print('date_str={}'.format(date_str))
        date_list.append(date_str)
 
    print('date_list={}'.format(date_list))
    return date_list
 
#从一个时间段获取其中的每一月,可以自定义时间间隔
def getBetweenEveryMonth(begin_date,end_date):
    date_list = []
    begin_date = datetime.datetime.strptime(begin_date, "%Y-%m-%d")
    end_date = datetime.datetime.strptime(end_date, "%Y-%m-%d")
    # end_date = datetime.datetime.strptime(time.strftime('%Y-%m-%d', time.localtime(time.time())), "%Y-%m-%d")
    while begin_date <= end_date:
        date_str = begin_date.strftime("%Y-%m-%d")
        begin_date = add_months_start(begin_date, 1)
        date_end=get_this_month_end(date_str)
        date_list.append((date_str+' 00:00:00',date_end))
        
    print('date_list={}'.format(date_list))
    return date_list
 
 
def add_months_start(dt, months):
    month = int(dt.month - 1 + months)
    year = int(dt.year + month / 12)
    month = int(month % 12 + 1)
    day = min(dt.day, calendar.monthrange(year, month)[1])
    return dt.replace(year=year, month=month, day=day)
 
def add_months_end(dt, months):
    month = int(dt.month - 1 + months)
    year = int(dt.year + month / 12)
    month = int(month % 12 + 1)
    day = max(dt.day, calendar.monthrange(year, month)[1])
    return dt.replace(year=year, month=month, day=day)