1. 獲取datetime對(duì)象

1. 獲取當(dāng)前datetime對(duì)象

• 方法：datetime.now(cls, tz=None) -> datetime

• 參數(shù)說明：

  tz：時(shí)區(qū)信息，不傳該參數(shù)時(shí)，默認(rèn)使用當(dāng)?shù)貢r(shí)區(qū)

• 示例代碼：

now = datetime.now()
print(now)  # 2023-01-05 09:38:43.084062
print(type(now))  # datetime.datetime

如果需要指定tz時(shí)區(qū)，可以通過pytz.timezone來指定，需要提供時(shí)區(qū)標(biāo)識(shí)符，時(shí)區(qū)標(biāo)識(shí)符可在"\Lib\site-packages\pytz\zoneinfo"文件夾下查看

• 示例代碼：

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'))  # 上海和北京同屬于東八區(qū)，因此可以用“Asia/Shanghai”來作為東八區(qū)的標(biāo)識(shí)符
print(dt_shanghai)  # 2023-01-05 10:18:46.943553+08:00

2. 獲取當(dāng)前utc datetime對(duì)象

• 方法：datetime.utcnow(cls) -> datetime

• 示例代碼：

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

北京屬于東八區(qū)，比utc時(shí)間早8小時(shí)，即我們?cè)缟鲜c(diǎn)半的時(shí)候，正是utc時(shí)區(qū)中的凌晨兩點(diǎn)半。

3. 自定義datetime對(duì)象

2. datetime，str，timestamp相互轉(zhuǎn)換

2.1 str 轉(zhuǎn) datetime 和 timestamp

1. str轉(zhuǎn)datetime

• 方法：datetime.strptime(_date_string, _format) -> datetime

• 參數(shù)說明：

  • _date_string：時(shí)間字符串
  • _format：時(shí)間解析格式

• 示例代碼：

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

2. str轉(zhuǎn)timestamp

。。。。。。

2.2 datetime 轉(zhuǎn) str 和 timestamp

1. datetime對(duì)象 轉(zhuǎn) str

• 方法：datetime.strftime(format) -> str
• 示例代碼：

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

2. datetime對(duì)象 轉(zhuǎn) timestamp

• 方法：datetime.timestampe() -> float
• 示例代碼

from datetime import datetime

now = datetime.now()
timestamp = now.timestamp()
print(type(timestamp))  # <class 'float'>
print(timestamp)  # 1672900754.798144

2.3 timestamp 轉(zhuǎn) datetime對(duì)象 和 str

1. timestamp 轉(zhuǎn) datetime

• 方法

datetime.fromstamp(timestamp, tz=None) -> datetime

• 示例代碼

from datetime import datetime

timestamp = 1672899623
now = datetime.fromtimestamp(timestamp)
print(now)  # 2023-01-05 14:20:23
print(type(now))  # <class 'datetime.datetime'>

2. timestamp 轉(zhuǎn) utc datetime對(duì)象

• 方法

datetime.utcfromstamp(timestamp, tz=None) -> datetime

• 示例代碼

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實(shí)例方法

1. datetime.timestampe() -> float

• 示例代碼

from datetime import datetime

now = datetime.now()
timestamp = now.timestamp()
print(type(timestamp))  # <class 'float'>
print(timestamp)  # 1672900754.798144

2. datetime.timetuple() -> time.struct_time

• 示例代碼

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)

3. datetime.replace(year=None, month=None, day=None, hour=None, minute=None, second=None, microsecond=None, tzinfo=True, *, fold=None) -> datetime

• 示例代碼

>>> 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類方法

1.datetime.fromisocalendar(year, week, day) -> datetime

• 功能說明

  從國際標(biāo)準(zhǔn)化日歷中獲得相應(yīng)的datetime對(duì)象

• 示例代碼

>>> datetime.fromisocalendar(2023, 1, 1)
datetime.datetime(2023, 1, 2, 0, 0)  # 2023年中第1個(gè)星期的第1天是1月2號(hào)

2. datetime.fromisoformat(date_string) -> datetime

• 功能說明

  將符合isoformat時(shí)間格式的字符串轉(zhuǎn)為datetime對(duì)象。

  isoformat指的是符合國際標(biāo)準(zhǔn)ISO8601的日期和時(shí)間表示方式。該標(biāo)準(zhǔn)旨在提供一套沒有歧義的表示格式，并具有以下規(guī)則：

  • Year first, followed by month, then the day, each separated by a hyphen ("-")（按年月日的順序先后排列，并以'-'進(jìn)行分隔）
  • Numbers less than 10 preceded by a leading zero（小于10的數(shù)字前面加0）

• 示例代碼

>>> 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)