Currently i have the following timestamp format as below :
2018-04-02T09:00:00+09:30
How can i convert the timestamp above to suit the postgres's timestamp column like below?
2018-04-02 09:00:00 +09.30
Also how can use python to convert the xml timestamp first before loading into postgres table?
This doesn't require any conversion whatsoever, it's a regular ISO 8601 time stamp. PostgreSQL supports multiple input formats for time stamps
select timestamp with time zone '2018-04-02T09:00:00+09:30';
timestamptz
------------------------
2018-04-01 18:30:00-05
(1 row)
You'll notice it's storing it in UTC. That's what you want. From the docs,
For timestamp with time zone, the internally stored value is always in UTC (Universal Coordinated Time, traditionally known as Greenwich Mean Time, GMT). An input value that has an explicit time zone specified is converted to UTC using the appropriate offset for that time zone. If no time zone is stated in the input string, then it is assumed to be in the time zone indicated by the system's TimeZone parameter, and is converted to UTC using the offset for the timezone zone.
When a timestamp with time zone value is output, it is always converted from UTC to the current timezone zone, and displayed as local time in that zone. To see the time in another time zone, either change timezone or use the AT TIME ZONE construct (see Section 9.9.3).
If you know you will always get your data in that format, you can do something like:
>>> a = "2018-04-02T09:00:00+09:30"
>>>
>>> b = a.replace('T', ' ').replace('+', ' +')
>>> b
'2018-04-02 09:00:00 +09:30'
It is ugly, but it works.
It is always safer to interpret your input as a date and then print it in the desired format.
Related
I have the following timestamp 1550588656 which translates to 2019-02-19 15:04:16+00:00 in UTC time convention.
I want to convert it to my country's time convention (UTC or GMT -3 in this time of the year) so it should translate to 2019-02-19 12:04:16+00:00
I have read on other SO questions that first I have to convert the timestamp to an UTC aware Datetime object and then localize it, I'm doing it like this
# string format time
naive_datetime = datetime.fromtimestamp(timestamp).strftime('%Y-%m-%d %H:%M:%S')
# string parse time
naive_datetime = datetime.strptime(naive_datetime, "%Y-%m-%d %H:%M:%S")
# make naive Datetime object UTC aware
utc_datetime = naive_datetime.replace(tzinfo=pytz.UTC)
So now it's not a naive Datetime object, from here I should be able to localize it to my country's timezone. In Python that is pytz.timezone('America/Santiago')
So it should go something like this
cltime = pytz.timezone('America/Santiago')
local_datetime = utc_datetime.astimezone(cltime)
But I'm getting 2019-02-19 09:04:16-03:00 (UTC or GTM -6 ) as a result and I don't know why.
Can someone explain? My intuition tells me it's probably a simple thing I'm not looking at, but I've spent some minutes in it and I haven't been able to tell yet.
If you look at the documentation for fromtimestamp:
Return the local date and time corresponding to the POSIX timestamp
So the problem is that it is already doing a conversion from UTC to the local time, and you're doing it a second time.
First of all you have epoc time (UTC timestamp). You need to convert it into datetime object (native) which is followed by converting native time to aware time and than finally convert it to your local time.
Convert your timestamp to native datetime object
native_datetime = datetime.fromtimestamp(1550588656)
convert native datetime object to aware time (add timezone info, will add timezone info to native timezone UTC for current)
import pytz
utc_time = native_datetime.replace(tzinfo=pytz.timezone("UTC"))
localising aware datetime to your local datetime
local_time = utc_time.astimezone(pytz.timezone("America/Santiago"))
You can replace "America/Santiago" with your local time zone
I think this would help you to solve your problem. Thanks!
I have the following code:
import datetime
dt = 1546955400
print(datetime.datetime.fromtimestamp(dt))
When I run this code on my local machine, I get the correct (expected) time which is
2019-01-08 15:50:00.
However I tried running this exact same code on a VM and the result was
2019-01-08 13:50:00 (two hours earlier). Why is this is happening and how can I fix it so that I always get the first one regardless of where the code is running?
datetime.datetime.fromtimestamp() returns local time. From the documentation:
Return the local date and time corresponding to the POSIX timestamp, such as is returned by time.time(). If optional argument tz is None or not specified, the timestamp is converted to the platform’s local date and time, and the returned datetime object is naive.
The timestamp value is an offset in seconds from the UNIX epoch value, midnight 1 January 1970, in the UTC timezone. The local time is a system-wide configured offset from UTC, the local timezone.
If your VM is producing unexpected results, you need to configure the timezone of the OS.
Alternatively, ignore timezones and only deal with time in the UTC timezone. For timestamps, that means using the datetime.datetime.utcfromtimestamp() function.
Your specific timestamp is 13:50 UTC:
>>> dt = 1546955400
>>> from datetime import datetime
>>> datetime.utcfromtimestamp(dt)
datetime.datetime(2019, 1, 8, 13, 50)
>>> print(_)
2019-01-08 13:50:00
so your VM is either set to the UTC or the GMT timezone (the latter is currently at UTC+0, until the switch to the UK daylight saving timezone BST). Your local system is in a UTC+2 timezone, given your stated location from your profile that'd be EEE, Easter European Time.
Another option is to create a timezone-aware timestamp by passing in a tz argument. If you have a specific UTC offset, just create a datetime.timezone() instance for that offset:
utcplus2 = datetime.timezone(datetime.timedelta(hours=2))
datetime.datetime.fromtimestamp(dt, utcplus2)
However, it is usually better to store and operate on UTC datetime instances everywhere, and only convert to specific timezones when displaying information to users. This simplifies datetime handling as it lets you avoid a number of timezone corner cases and problems, such as mixing datetime information from different timezones and timezones with a summer and winter time distinction.
import arrow
print arrow.utcnow()
print arrow.utcnow().timestamp
print arrow.utcnow().to('Asia/Kolkata')
print arrow.utcnow().to('Asia/Kolkata').timestamp
I need the timestamp (in int) of 'Asia/Kolkata' timezone, which is +5:30 from utc.
arrow.utcnow() and arrow.utcnow().to('Asia/Kolkata') are coming out to be different and the second one is +5:30 the first, as expected.
However, arrow.utcnow().timestamp and arrow.utcnow().to('Asia/Kolkata').timestamp are still coming out to be same.
I am sure I am missing something very basic here, but can anyone explain this?
I think "timestamp", by definition, is always in UTC:
The Unix time (or Unix epoch or POSIX time or Unix timestamp) is a
system for describing points in time, defined as the number of seconds
elapsed since midnight proleptic Coordinated Universal Time (UTC) of
January 1, 1970, not counting leap seconds.
If you take your localized time string, convert it to a UTC date time (that is, 5pm Kolkata time becomes 5pm UTC), then you can get a timestamp that corresponds to the local clock time. Example:
import arrow
print arrow.utcnow()
print arrow.utcnow().timestamp
kolkata = arrow.utcnow().to('Asia/Kolkata')
print kolkata.replace(tzinfo='UTC').timestamp
Timestamps are UTC, this is also described in the Arrow docs
timestamp
Returns a timestamp representation of the Arrow object, in
UTC time.
Arrow will let you convert a non-UTC timestamp into arrow time but it won't let you shoot yourself in the foot by generating non-UTC timestamps for you.
classmethod fromtimestamp(timestamp, tzinfo=None)
Constructs an Arrow
object from a timestamp, converted to the given timezone.
Parameters: timestamp – an int or float timestamp, or a str that
converts to either. tzinfo – (optional) a tzinfo object. Defaults to
local time. Timestamps should always be UTC. If you have a non-UTC
timestamp:
arrow.Arrow.utcfromtimestamp(1367900664).replace(tzinfo='US/Pacific')
<Arrow [2013-05-07T04:24:24-07:00]>
The full docs are here:
http://arrow.readthedocs.io/en/latest/
I am currently having a Db in Postgres with a timestamp column setup as below:
ts timestamp with time zone not null default (now() at time zone 'utc'),
this is saving the ts :
2017-08-22 10:34:21.547703+00
This the utc time.
2017-08-22T10:34:21.547703+00:00 format ISO8601
I found this 'YYYY-MM-DD"T"HH24:MI:SS:MS"Z"' but I still do not want the 'Z'
I am not finding the way to add the Tbetween date and time and also why the TZ show as +00 instead of +00:00 in my current format, I do not want the space and also the TZ should also reflect the minutes. Right now it's only hour
I wanted to convert the UNIX time into local date and time. I am getting the UNIX timestamp value from my server but when I convert the UNIX using these set of code I get a time which is 1 hour 30 min less than the actual time. But when I take the raw timestamp data and check in the online UNIX to local date and time converter I get the correct time.
import datetime
time_local = datetime.datetime.fromtimestamp(1502705627085/1e3)
print time_local
is your timezone correct on your system ?
From the python datetime documentation :
classmethod datetime.fromtimestamp(timestamp[, tz])
Return the local date and time corresponding to the POSIX timestamp, such as is returned by time.time(). If optional argument tz is None or not specified, the timestamp is converted to the platform’s local date and time, and the returned datetime object is naive.
If you cannot change your system's timezone, you can specify a tz as explained in the datetime module documentation.
import datetime
import tzlocal
time_local = datetime.datetime.fromtimestamp(1502705627085/1e3, tzlocal.get_localzone())
print time_local