假设你获取了用户输入的日期和时间如2015-1-21 9:01:30
,以及一个时区信息如UTC+5:00
,均是str
,请编写一个函数将其转换为timestamp:
from datetime import datetime,timedelta,timezone
import re
def to_timestamp(dt_str, tz_str):
dt=datetime.strptime(dt_str,"%Y-%m-%d %H:%M:%S")
pattern=re.compile(r"UTC(.+?):")
tzstr=pattern.match(tz_str).group(1)
tz=timezone(timedelta(hours=int(tzstr)))
dttz=dt.replace(tzinfo=tz)
return dttz.timestamp()
t1 = to_timestamp('2015-6-1 08:10:30', 'UTC+7:00')
assert t1 == 1433121030.0, t1
t2 = to_timestamp('2015-5-31 16:10:30', 'UTC-09:00')
assert t2 == 1433121030.0, t2
print('ok')
str转换为datetime
转换方法是通过datetime.strptime()
实现,需要一个日期和时间的格式化字符串
>>> from datetime import datetime
>>> cday = datetime.strptime('2015-6-1 18:19:59', '%Y-%m-%d %H:%M:%S')
>>> print(cday)
2015-06-01 18:19:59
datetime转换为timestamp
把一个datetime
类型转换为timestamp只需要简单调用timestamp()
方法:
>>> from datetime import datetime
>>> dt = datetime(2015, 4, 19, 12, 20) # 用指定日期时间创建datetime
>>> dt.timestamp() # 把datetime转换为timestamp
1429417200.0
本地时间转换为UTC时间
一个datetime
类型有一个时区属性tzinfo
,但是默认为None
,所以无法区分这个datetime
到底是哪个时区,除非强行给datetime
设置一个时区
>>> from datetime import datetime, timedelta, timezone
>>> tz_utc_8 = timezone(timedelta(hours=8)) # 创建时区UTC+8:00
>>> now = datetime.now()
>>> now
datetime.datetime(2015, 5, 18, 17, 2, 10, 871012)
>>> dt = now.replace(tzinfo=tz_utc_8) # 强制设置为UTC+8:00
>>> dt
datetime.datetime(2015, 5, 18, 17, 2, 10, 871012, tzinfo=datetime.timezone(datetime.timedelta(0, 28800)))