1. 获取datetime对象
- 获取当前datetime对象
-
方法：
datetime.now(cls, tz=None) -> datetime -
参数说明：
tz：时区信息，不传该参数时，默认使用当地时区
-
示例代码：
now = datetime.now()
print(now) # 2023-01-05 09:38:43.084062
print(type(now)) # datetime.datetime
如果需要指定tz时区，可以通过pytz.timezone来指定，需要提供时区标识符，时区标识符可在"\Lib\site-packages\pytz\zoneinfo"文件夹下查看
- 示例代码：
import pytz
from datetime import datetime
dt_mexico = datetime.now(pytz.timezone('America/Mexico_City'))
print(dt_mexico) # 2023-01-04 20:18:46.943553-06:00
dt_shanghai = datetime.now(pytz.timezone('Asia/Shanghai')) # 上海和北京同属于东八区，因此可以用“Asia/Shanghai”来作为东八区的标识符
print(dt_shanghai) # 2023-01-05 10:18:46.943553+08:00
- 获取当前utc datetime对象
-
方法：
datetime.utcnow(cls) -> datetime -
示例代码：
from datetime import datetime
china_time = datetime.now()
utc_time = datetime.utcnow()
print(china_time) # 2023-01-05 10:30:26.716563
print(utc_time) # 2023-01-05 02:30:26.716563
北京属于东八区，比utc时间早8小时，即我们早上十点半的时候，正是utc时区中的凌晨两点半。
- 自定义datetime对象
2. datetime，str，timestamp相互转换
2.1 str 转 datetime 和 timestamp
- str转datetime
-
方法：
datetime.strptime(_date_string, _format) -> datetime -
参数说明：
- _date_string：时间字符串
- _format：时间解析格式
-
示例代码：
from datetime import datetime
beijing_time_str = "2023-01-05 11:45:33"
datetime_beijing = datetime.strptime(beijing_time_str, "%Y-%m-%d %H:%M:%S")
print(type(datetime_beijing)) # <class 'datetime.datetime'>
print(datetime_beijing) # 2023-01-05 11:45:33
- str转timestamp
。。。。。。
2.2 datetime 转 str 和 timestamp
- datetime对象 转 str
- 方法：
datetime.strftime(format) -> str - 示例代码：
from datetime import datetime
now = datetime.now()
now_str = now.strftime("%Y-%m-%d %H:%M:%S")
print(type(now_str)) # <class 'str'>
print(now_str) # 2023-01-05 12:09:04
- datetime对象 转 timestamp
- 方法：
datetime.timestampe() -> float - 示例代码
from datetime import datetime
now = datetime.now()
timestamp = now.timestamp()
print(type(timestamp)) # <class 'float'>
print(timestamp) # 1672900754.798144
2.3 timestamp 转 datetime对象 和 str
- timestamp 转 datetime
- 方法
datetime.fromstamp(timestamp, tz=None) -> datetime
- 示例代码
from datetime import datetime
timestamp = 1672899623
now = datetime.fromtimestamp(timestamp)
print(now) # 2023-01-05 14:20:23
print(type(now)) # <class 'datetime.datetime'>
- timestamp 转 utc datetime对象
- 方法
datetime.utcfromstamp(timestamp, tz=None) -> datetime
- 示例代码
from datetime import datetime
timestamp = 1672899623
now = datetime.utcfromtimestamp(timestamp)
print(now) # 2023-01-05 06:20:23
print(type(now)) # <class 'datetime.datetime'>
3. datetime实例方法
datetime.timestampe() -> float
- 示例代码
from datetime import datetime
now = datetime.now()
timestamp = now.timestamp()
print(type(timestamp)) # <class 'float'>
print(timestamp) # 1672900754.798144
datetime.timetuple() -> time.struct_time
- 示例代码
from datetime import datetime
now = datetime.now()
timetuple = now.timetuple()
print(type(timetuple)) # <class 'time.struct_time'>
print(timetuple) # time.struct_time(tm_year=2023, tm_mon=1, tm_mday=5, tm_hour=14, tm_min=44, tm_sec=3, tm_wday=3, tm_yday=5, tm_isdst=-1)
datetime.replace(year=None, month=None, day=None, hour=None, minute=None, second=None, microsecond=None, tzinfo=True, *, fold=None) -> datetime
- 示例代码
>>> from datetime import datetime
>>> now = datetime.now()
>>> now
datetime.datetime(2023, 1, 5, 14, 56, 10, 892657)
>>> now.replace(year=2022)
datetime.datetime(2022, 1, 5, 14, 56, 10, 892657)
4. datetime类方法
1.datetime.fromisocalendar(year, week, day) -> datetime
-
功能说明
从国际标准化日历中获得相应的datetime对象
-
示例代码
>>> datetime.fromisocalendar(2023, 1, 1)
datetime.datetime(2023, 1, 2, 0, 0) # 2023年中第1个星期的第1天是1月2号
datetime.fromisoformat(date_string) -> datetime
-
功能说明
将符合isoformat时间格式的字符串转为datetime对象。
isoformat指的是符合国际标准ISO8601的日期和时间表示方式。该标准旨在提供一套没有歧义的表示格式，并具有以下规则：
- Year first, followed by month, then the day, each separated by a hyphen ("-")（按年月日的顺序先后排列，并以'-'进行分隔）
- Numbers less than 10 preceded by a leading zero（小于10的数字前面加0）
-
示例代码
>>> from datetime import datetime
>>> datetime.fromisoformat("2022-01-05")
datetime.datetime(2022, 1, 5, 0, 0)
>>> datetime.fromisoformat("2022-01-05 15:24:23")
datetime.datetime(2022, 1, 5, 15, 24, 23)
>>> datetime.fromisoformat("2022-01-05T15:24:23")
datetime.datetime(2022, 1, 5, 15, 24, 23)
>>> datetime.fromisoformat("2022-01-05T15:24:23.434")
datetime.datetime(2022, 1, 5, 15, 24, 23, 434000)