Unix timestamp converting by python pandas

Question

I want to convert a time(String) to unix timestamp, then convert it back to readable datetime, however, there are 7 hours different. What is the problem in my python code?

import datetime

#Convert a Datetime String to unix timestamp   
def get_Timestamp_from_String(datetimeStr):    

    timestamp = int(datetime.datetime.strptime(datetimeStr, '%Y-%m-%d %H:%M:%S').timestamp())*1000

    return timestamp


# Convert unix timestamp to DateTime    
def get_Datetime_from_Timestamp(timestamp):

    dt = pd.to_datetime(timestamp, unit='ms')

    return dt

Test the datetime: "2016-04-01 01:10:04", however, if I convert it back, then I got the result: '2016-04-01 08:10:04', there are 7 hours different

timestamp = get_Timestamp_from_String("2016-04-01 01:10:04")
res = get_Datetime_from_Timestamp(timestamp)
print(res)

>>>Timestamp('2016-04-01 08:10:04')

What is the problem in my code?

@IanS I feel very strange, I didn't give any timezone in both functions, so the default timezone should be applied. — xirururu
– xirururu, Commented Sep 13, 2017 at 12:12

jezrael · Accepted Answer · 2017-09-13 12:06:43Z

3

I think you need to_datetime twice, for ms divide by 10**6:

datetimeStr = '2016-04-01 01:10:04'
timestamp = pd.to_datetime(datetimeStr).value //10**6
print (timestamp)
1459473004000

dt = pd.to_datetime(timestamp, unit='ms')
print (dt)
2016-04-01 01:10:04

For ns, native format of timestamps in numpy dividing is not necessary:

datetimeStr = '2016-04-01 01:10:04'
timestamp = pd.to_datetime(datetimeStr).value
print (timestamp)
1459473004000000000

dt = pd.to_datetime(timestamp, unit='ns')
print (dt)
2016-04-01 01:10:04

But if have timezone information:

datetimeStr = '2016-04-01 01:10:04-07:00'
timestamp = pd.to_datetime(datetimeStr).value //10**6
print (timestamp)
1459498204000

dt = pd.to_datetime(timestamp, unit='ms')
print (dt)
2016-04-01 08:10:04

edited Sep 13, 2017 at 12:06

answered Sep 13, 2017 at 11:53

jezrael

868k103 gold badges1.4k silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

xirururu Over a year ago

@jezrael , thanks very much for the answer. But, I think, it is so strange, that the result from pd.to_datetime(...) is different from datetime.datetime.strptime(...), I can not understand it...

jezrael Over a year ago

Hard question for me - but I think pandas to_datetime is more general.

Collectives™ on Stack Overflow

Unix timestamp converting by python pandas

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related