python datetime模块用法

1. 创建naive（无时区信息）的datetime对象

import datetime  
 
dt_utc = datetime.datetime.utcnow()

dt_utc # datetime.datetime(2019, 2, 1, 10, 53, 34, 145034)

dt_utc.tzinfo # None 

dt_local = datetime.datetime.now()

dt_local.tzinfo # None 

# tzinfo为None的datetime对象is naive（不知道怎么翻译好。。。）

# tzinfo为tzinfo对象的None的datetime对象is aware。

# 只有都为naive或者都为aware才可以相互比较

2. 创建的aware（有时区信息）的datetime对象

import datetime  
 
dt_utc = datetime.datetime.utcnow()

dt_utc_aware = dt.replace(tzinfo=datetime.timezone.utc)

dt_utc_aware.tzinfo # datetime.timezone.utc

dt_local = datetime.datetime.now()

dt_local_aware = dt_local.replace(tzinfo=datetime.tzinfo(datetime.timedelta(hours=8)))

3. datetime对象的时区转换

import datetime  
 
dt_utc = datetime.datetime.utcnow()

dt_utc_aware = dt.replace(tzinfo=datetime.timezone.utc)

dt_utc_aware.tzinfo # datetime.timezone.utc

dt_local_aware = dt_utc_aware.astimezone(datetime.timezone(datetime.timedelta(hours=8))) # 转为北京时间

4. datetime对象和时间戳互转

import datetime  
 
import time

stamp = time.time() # 获取时间戳

dt_utc = datetime.datetime.utcfromtimestamp(stamp) # 转为datetime

# datetime.datetime(2019, 2, 1, 12, 52, 59, 268168)

dt_local = datetime.datetime.fromtimestamp(stamp)

# datetime.datetime(2019, 2, 1, 20, 52, 59, 268168)

stp = dt_utc.timestamp() # 转为时间戳，时间戳唯一，不因时区变化

4. datetime对象和date对象互转

import datetime  

d_local = datetime.date.today() # 获取date

dt_utc = datetime.datetime.fromordinal(d_local.toordinal()) # 转为datetime

# datetime.datetime(2019, 2, 1, 0, 0)

d_ = dt_utc.date() # 转为date

# datetime.date(2019, 2, 1)