Python 时间相关处理

datetime

????????from datetime import datetime, timedelta, date

????????fmt：指定日期字符串的格式，其中%Y表示四位年份，%m表示两位月份，%d表示两位日

?

????????将日期字符串转为日期对象

????????????????datetime.striptime(date_str,fmt)

date_str = "2022-01-01"
date_obj = datetime.strptime(date_str, "%Y-%m-%d")
print(date_obj)

# 输出：2022-01-01 00:00:00

????????将日期对象转为字符串

????????????????datetime.striptime(fmt)

date_obj = datetime(2022, 1, 1)
date_str = date_obj.strftime("%Y-%m-%d")
print(date_str)

# 输出：2022-01-01

????????timedelta

????????????????timedelta是datetime模块中的一个类，用于表示时间间隔（即时间差）。它可以用来进行时间的加减运算，并且可以表示不同单位的时间差，如天、小时、分钟。常用于对天的处理，例如前一天、后一天等。

timedelta(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0)

????????????????天的间隔

from datetime import datetime, timedelta, date

delta = timedelta(days=1)
print(delta)

# 输出： 1 day, 0:00:00


date_obj = datetime(2022, 1, 1)
previous_day = date_obj - timedelta(days=1)
next_day = date_obj + timedelta(days=1)
print(previous_day)
print(next_day)

# 输出：
# 2021-12-31 00:00:00
# 2022-01-02 00:00:00

relativedelta

????????relativedelta是dateutil库中的一个类，用于计算两个日期之间的差距，并且可以实现灵活的日期运算。relativedelta相比timedelta更为灵活，可以实现更复杂的日期运算，如计算两个日期之间的年数、月数、星期数等。

????????dateutil属于第三方库，需要安装后才能使用。

from dateutil.relativedelta import relativedelta

relativedelta(years=0, months=0, days=0, weeks=0, hours=0, minutes=0, seconds=0, microseconds=0)

????????月的间隔

date_obj = datetime(2022, 1, 1)
previous_month = date_obj - relativedelta(months=1)
next_month = date_obj + relativedelta(months=1)
print(previous_month)
print(next_month)

# 输出
# 2021-12-01 00:00:00
# 2022-02-01 00:00:00

其他功能

????????博主也总结了自己常用的几个功能，封装成了函数，供大家参考使用

????????分别是三个功能：拆分年月日时分秒、拆分年月日、获取两个时间间隔的日期列表

from datetime import datetime, timedelta

from ProjectStart.set_logger import USE_LOGGER


# 拆分为年月日 与 时分秒
def handle_date_and_time(start_time, end_time, fmt='%Y-%m-%d %H:%M:%S'):
    """
    将传入的开始和结束时间，转为字符串拆分成【年月日】 与 【时分秒】
    :param start_time: 开始日期
    :param end_time: 结束日期
    :param fmt: 对应的日期格式
    :return: 返回拆分后的值
    """
    data_dict = {'data': "", "warning_info": "", "error_info": "", }

    try:
        # 获取拆分后的时间格式
        if isinstance(start_time, str) and isinstance(end_time, str):
            start_date_str = start_time.split(" ")[0]
            start_time_str = start_time.split(" ")[-1]
            end_date_str = end_time.split(" ")[0]
            end_time_str = end_time.split(" ")[-1]
        elif isinstance(start_time, datetime) and isinstance(end_time, datetime):
            try:
                start_date_str = datetime.strftime(start_time, fmt).split(" ")[0]
                start_time_str = datetime.strftime(start_time, fmt).split(" ")[-1]
                end_date_str = datetime.strftime(end_time, fmt).split(" ")[0]
                end_time_str = datetime.strftime(end_time, fmt).split(" ")[-1]
            except ValueError:
                data_dict["error_info"] = "日期类型格式转换失败"
                return data_dict
        else:
            data_dict["error_info"] = "数据类型不一致"
            return data_dict

        data_dict["data"] = start_date_str, start_time_str, end_date_str, end_time_str
    except Exception as e:
        USE_LOGGER.exception(e)
    finally:
        return data_dict


# 拆分日 日期
def split_day_time(start_time, end_time, whole_fmt='%Y-%m-%d %H:%M:%S', date_fmt='%Y-%m-%d', split_day=1):
    """
    按照指定拆分的日间隔，拆分为列表
    :param start_time: 开始日期
    :param end_time: 结束日期
    :param whole_fmt: 对应的整个日期格式
    :param date_fmt: 对应日的日期格式
    :param split_day: 拆分的间隔
    :return: 返回嵌套列表，每一个子列表为固定时间间隔的值
    """
    data_dict = {'data': "", "warning_info": "", "error_info": "", }

    ever_date_list = []
    handle_result_dict = handle_date_and_time(start_time, end_time, fmt=whole_fmt)
    if handle_result_dict["error_info"]: return
    start_date_str, start_time_str, end_date_str, end_time_str = handle_result_dict["data"]

    if start_date_str == start_time_str or end_date_str == end_time_str:
        start_time_str = ""
        end_time_str = ""

    try:
        ever_date = datetime.strptime(start_date_str, date_fmt).date()
        end_date = datetime.strptime(end_date_str, date_fmt).date()

        if ever_date == end_date:
            ever_date_list.append([f"{ever_date} {start_time_str}" if start_time_str else f"{ever_date}",
                                   f"{ever_date} {end_time_str}" if end_time_str else f"{ever_date}"])
        else:
            while ever_date < end_date:
                new_start_date = f"{ever_date} {start_time_str}" if start_time_str else f"{ever_date}"
                ever_date += timedelta(days=split_day)
                ever_date = ever_date
                new_end_date = f"{ever_date} {end_time_str}" if end_time_str else f"{ever_date}"
                ever_date_list.append([new_start_date, new_end_date])
        data_dict["data"] = ever_date_list
    except ValueError:
        data_dict["error_info"] = "日期类型格式转换失败"
        return data_dict
    finally:
        return data_dict


# 获取每一天时间列表
def get_day_date_list(start_time, end_time, whole_fmt='%Y-%m-%d', date_fmt='%Y-%m-%d', out_fmt='%Y-%m-%d'):
    data_dict = {'data': "", "warning_info": "", "error_info": "", }

    day_date_list = []

    handle_result_dict = handle_date_and_time(start_time, end_time, fmt=whole_fmt)
    if handle_result_dict["error_info"]: return
    try:
        start_date_str, start_time_str, end_date_str, end_time_str = handle_result_dict["data"]
        start_date = datetime.strptime(start_date_str, date_fmt).date()
        end_date = datetime.strptime(end_date_str, date_fmt).date()
        delta = end_date - start_date

        # 生成每一天的日期并添加到列表中
        for i in range(delta.days + 1):
            date = start_date + timedelta(days=i)
            day_date_list.append(date.strftime(out_fmt))
        data_dict["data"] = day_date_list
    except ValueError:
        data_dict["error_info"] = "日期类型格式转换失败"
        return data_dict
    finally:
        return data_dict


if __name__ == '__main__':
    # s_time = "2024-01-09 00:00:00"
    # e_time = "2024-01-12 00:00:00"
    # w_fmt = '%Y-%m-%d %H:%M:%S'
    # d_fmt = '%Y-%m-%d'

    s_time = "2024-01-09"
    e_time = "2024-01-20"
    w_fmt = '%Y-%m-%d'
    d_fmt = '%Y-%m-%d'
    result = split_day_time(s_time, e_time, w_fmt, d_fmt)

    print(result)