看起来
astimezone
比
localize
快 3 倍以上。是否有理由使用
localize
而不是
astimezone
?
-------- Trial Name: Convert nonaware datetimes to timezone aware via localize
Totaltime: 1.854642400s
Time per loop: 18.546us
-------- Trial Name: Convert nonaware datetimes to timezone aware via astimezone
Totaltime: 0.584159600s
Time per loop: 5.842us
在运行 Windows 10 Home 的 Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz 2.81 GHz、16GB RAM 上进行的试验。
import timeit
numberOfTrials = 100000
def myTimeit(trialName, mysetup, mycode, numberOfTrials):
print(f'-------- Trial Name: {trialName}')
# timeit statement
totalTime = timeit.timeit(setup=mysetup,
stmt=mycode,
number=numberOfTrials)
print(f"Totaltime: {totalTime:0,.9f}s")
print(f"Time per loop: {totalTime / numberOfTrials * 1e6:0.3f}us")
print()
return totalTime
mysetup = '''
from datetime import datetime
import pytz
notTimezoneAware_datetime = datetime.strptime("220105 230310", '%y%m%d %H%M%S')
TOKYO_tz = pytz.timezone('Asia/Tokyo')
'''
myTimeit(trialName='Convert nonaware datetimes to timezone aware via localize',
mysetup=mysetup,
mycode='TOKYO_tz.localize(notTimezoneAware_datetime)',
numberOfTrials=numberOfTrials)
myTimeit(trialName='Convert nonaware datetimes to timezone aware via astimezone',
mysetup=mysetup,
mycode='notTimezoneAware_datetime.astimezone(TOKYO_tz)',
numberOfTrials=numberOfTrials)
localize
设置原始日期时间对象的时区。它不会更改对象的属性(日期/时间)
astimezone
接受给定的日期时间对象(无论是天真的还是有意识的),并将日期/时间转换为所需的时区。如果日期时间对象很简单,则假定它是本地时间。
from datetime import datetime
import pytz
# just localize to a certain time zone.
pytz.timezone("America/Denver").localize(datetime(2022, 5, 15))
Out[3]: datetime.datetime(2022, 5, 15, 0, 0, tzinfo=<DstTzInfo 'America/Denver' MDT-1 day, 18:00:00 DST>)
# convert to the desired time zone; note that my local time zone is UTC+2
# US/Denver is at UTC-6 on May 15th 2022, so total shift is 8 hours:
datetime(2022, 5, 15).astimezone(pytz.timezone("America/Denver"))
Out[4]: datetime.datetime(2022, 5, 14, 16, 0, tzinfo=<DstTzInfo 'America/Denver' MDT-1 day, 18:00:00 DST>)
回答问题:不,没有任何好处。您正在处理具有不同目的的方法。
from zoneinfo import ZoneInfo
%timeit pytz.timezone("America/Denver").localize(datetime(2022, 5, 15))
16.8 µs ± 30.3 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)
%timeit datetime(2022, 5, 15).replace(tzinfo=ZoneInfo("America/Denver"))
1.19 µs ± 5.83 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)