CODEWITHSUNDEEP
pythonpandasdatetimetimezone-offsetpytz
FL44ME
FL44ME

Reputation: 49

Python - How to convert datetime object to timezone given as string in a column?

I have a column of UTC times which I need to convert to 'local' times based on the UTC timezone provided in a second column as a string. How do I assign a timezone using pytz to the time in the column based on string UTC timezone provided? enter image description here

Upvotes: 0

Views: 727

Answers (2)

FObersteiner
FObersteiner

Reputation: 25544

Parse the date/time columns to datetime; for the UTC (offset) column do the same but just keep the offset. Then convert to this offset as time zone. EX:

import pandas as pd

df = pd.DataFrame({"bed_time": ["2021-03-28 00:40:00.000","2021-03-28 06:00:00.000"],
                   "wake_time": ["2021-03-27 00:00:00.000","2021-03-27 08:10:00.000"],
                   "UTC": ["+0400","+0500"]}) # adjusted example here to take mixed UTC offsets in to account

# parse to UTC and get the tz as a fixed offset
df['bed_time'] = pd.to_datetime(df['bed_time'], utc=True)
df['wake_time'] = pd.to_datetime(df['wake_time'], utc=True)
df['offset'] = pd.to_datetime(df['UTC'], format='%z').apply(lambda t: t.tz)

Now we have UTC and a fixed offset time zone;

df
                   bed_time  ...                 offset
0 2021-03-28 00:40:00+00:00  ...  pytz.FixedOffset(240)
1 2021-03-28 06:00:00+00:00  ...  pytz.FixedOffset(300)

So we can convert to that;

# convert to tz individually
df['bed_time'] = df.apply(lambda row: row['bed_time'].tz_convert(row['offset']), axis=1)
df['wake_time'] = df.apply(lambda row: row['wake_time'].tz_convert(row['offset']), axis=1)

to get

df
                    bed_time  ...                 offset
0  2021-03-28 04:40:00+04:00  ...  pytz.FixedOffset(240)
1  2021-03-28 11:00:00+05:00  ...  pytz.FixedOffset(300)

Upvotes: 1

openwld
openwld

Reputation: 916

import pytz

# fmt: Etc/GMT{+,-}{tm}
def format_tz(s:str):
    icon = '+' # default to plus sign
    s = s.strip()
    if s[0] == '-':
        icon = '-' # change to minus if is minus
    if s[0] in ('+', '-'):
        s = s[1:] # strip pluses and minuses
    i:int = int(s) # change to integer
    return pytz.timezone(f'Etc/GMT{icon}{i}') # convert to timezone

and for the time(excl. milliseconds)

# fmt: yyyy-mm-dd hh:mm:ss.MMM
def format_time(s:str):
    return time.strptime(s[:-5], '%Y-%m-%d %H:%M:%S')

Upvotes: 1

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