UTC到CST时间转换使用pytz python包

Question

我有嵌套的 json 文件，该文件具有 UTC 格式的时区下面贴出代码

def extract_json_data(fpath):
    print("Extracting " + fpath)
    f = open(fpath, 'r')
    json_data = json.loads(f.read())
    data = json_data['data']
    dt = datetime.datetime.strptime(json_data['time'], "%Y-%m-%dT%H:%M:%SZ")
    dt_cst = dt.astimezone(timezone('US/Central'))
    _ = [row.update({'time_UTC': dt.strftime("%Y-%m-%dT%H:%M:%SZ"),
                     'time_CST': dt_cst.strftime("%Y-%m-%dT%H:%M:%S CST")}) for row in data]

Answer 1

使用格式字符串解析时区，以便您使用的日期时间对象是时区感知的：

from datetime import datetime

# the string actually has timezone information: Z (UTC)
timestring = "2019-01-01T00:00:00Z"

# wrong:
dt = datetime.strptime(timestring, "%Y-%m-%dT%H:%M:%SZ")
# dt is naive:
# datetime.datetime(2019, 1, 1, 0, 0)

# right:
dt = datetime.strptime(timestring, "%Y-%m-%dT%H:%M:%S%z")
# dt now knows it's in UTC:
# datetime.datetime(2019, 1, 1, 0, 0, tzinfo=datetime.timezone.utc)

现在您可以将 datetime 对象的时间更改为不同的时区：

import pytz
tz = pytz.timezone('US/Central')
dt_cst = dt.astimezone(tz)
# datetime.datetime(2018, 12, 31, 18, 0, tzinfo=<DstTzInfo 'US/Central' CST-1 day, 18:00:00 STD>)

---

更方便的解决方案是跳过pytz 并改用dateutil：

import dateutil
timestring = "2019-01-01T00:00:00Z"
dt = dateutil.parser.parse(timestring)

# dt
# datetime.datetime(2019, 1, 1, 0, 0, tzinfo=tzutc())

Answer 2

这是一种方法：

import datetime
from dateutil import tz

# create a time-zone object representing UTC. 
from_zone = tz.gettz('UTC')

# Create another time zone object, representing the target time zone. 
# note that according to the tz package documentation 
# (https://dateutil.readthedocs.io/en/stable/tz.html#dateutil.tz.gettz), 
# they have Windows-specific time-zone names support. 
to_zone = tz.gettz('America/Chicago')

# This is just a sample dictionary, so I cam extract the 'time' 
# field like you do in your code. It's really not needed here. 
json_data = {'time': "2020-05-16T08:17:42Z"} # an example for a datetime

# Create a datetime object, representing the UTC time. 
utc = datetime.datetime.strptime(json_data['time'], "%Y-%m-%dT%H:%M:%SZ")

# now replace the timezone field of the newly created datetime object, 
# so it would be UTC. 
utc = utc.replace(tzinfo=from_zone)

# Convert time zone from UTC to central
central = utc.astimezone(to_zone)

print(central)

你会得到：

2020-05-16 03:17:42-05:00