ISO time ISO 8601 in Python

Question

I have a file  In Python  I would like to take its creation time  and convert it to an ISO time  ISO 8601  string while preserving the fact that it was created in the Eastern Time Zone  ET    How do I take the file s ctime and convert it to an ISO time string that indicates the Eastern Time Zone  and takes into account daylight savings time  if necessary

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ISO 8601 Time Representation  The international standard ISO 8601 describes a string representation for dates and times  Two simple examples of this format are  2010-12-16 17 22 15 20101216T172215    which both stand for the 16th of December 2010   but the format also allows for sub-second resolution times and to specify time zones  This format is of course not Python-specific  but it is good for storing dates and times in a portable format  Details about this format can be found in the Markus Kuhn entry   I recommend use of this format to store times in files   One way to get the current time in this representation is to use strftime from the time module in the Python standard library    gt  gt  gt  from time import strftime  gt  gt  gt  strftime   Y- m- d  H  M  S    2010-03-03 21 16 45    You can use the strptime constructor of the datetime class    gt  gt  gt  from datetime import datetime  gt  gt  gt  datetime strptime  2010-06-04 21 08 12     Y- m- d  H  M  S   datetime datetime 2010  6  4  21  8  12    The most robust is the Egenix mxDateTime module    gt  gt  gt  from mx DateTime ISO import ParseDateTimeUTC  gt  gt  gt  from datetime import datetime  gt  gt  gt  x   ParseDateTimeUTC  2010-06-04 21 08 12    gt  gt  gt  datetime fromtimestamp x  datetime datetime 2010  3  6  21  8  12    References   The Python time module documentation The Python datetime class documentation The Egenix mxDateTime class

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For those who are looking for a date-only solution  it is  import datetime  datetime date today   isoformat

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The ISO 8601 time format does not store a time zone name  only the corresponding UTC offset is preserved   To convert a file ctime to an ISO nbsp 8601 time string while preserving the UTC offset in Python nbsp 3    gt  gt  gt  import os  gt  gt  gt  from datetime import datetime  timezone  gt  gt  gt  ts   os path getctime some file   gt  gt  gt  dt   datetime fromtimestamp ts  timezone utc   gt  gt  gt  dt astimezone   isoformat    2015-11-27T00 29 06 839600-05 00    The code assumes that your local timezone is  Eastern Time Zone  ET  and that your system provides a correct UTC offset for the given POSIX timestamp  ts   i e   Python has access to a historical timezone database on your system or the time zone had the same rules at a given date   If you need a portable solution  use the pytz module that provides access to the tz database    gt  gt  gt  import os  gt  gt  gt  from datetime import datetime  gt  gt  gt  import pytz    pip install pytz  gt  gt  gt  ts   os path getctime some file   gt  gt  gt  dt   datetime fromtimestamp ts  pytz timezone  America New York     gt  gt  gt  dt isoformat    2015-11-27T00 29 06 839600-05 00    The result is the same in this case   If you need the time zone name abbreviation zone id  store it separately    gt  gt  gt  dt astimezone   strftime   Y- m- d  H  M  S z   Z     2015-11-27 00 29 06-0500  EST     Note  no    in the UTC offset and EST timezone abbreviation is not part of the ISO nbsp 8601 time format  It is not unique   Different libraries different versions of the same library may use different time zone rules for the same date timezone  If it is a future date then the rules might be unknown yet  In other words  the same UTC time may correspond to a different local time depending on what rules you use -- saving a time in ISO nbsp 8601 format preserves UTC time and the local time that corresponds to the current time zone rules in use on your platform  You might need to recalculate the local time on a different platform if it has different rules

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ISO 8601 allows a compact representation with no separators except for the T  so I like to use this one-liner to get a quick timestamp string   gt  gt  gt  datetime datetime utcnow   strftime  quot  Y m dT H M S  fZ quot    20180905T140903 591680Z   If you don t need the microseconds  just leave out the   f part   gt  gt  gt  datetime datetime utcnow   strftime  quot  Y m dT H M SZ quot    20180905T140903Z   For local time   gt  gt  gt  datetime datetime now   strftime  quot  Y m dT H M S quot    20180905T140903   Edit  After reading up on this some more  I recommend you leave the punctuation in  RFC 3339 recommends that style because if everyone uses punctuation  there isn t a risk of things like multiple ISO 8601 strings being sorted in groups on their punctuation  So the one liner for a compliant string would be   gt  gt  gt  datetime datetime now   strftime  quot  Y- m- dT H  M  SZ quot    2018-09-05T14 09 03Z

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I ve developed this function   def iso 8601 format dt          YYYY-MM-DDThh mm ssTZD  1997-07-16T19 20 30-03 00          if dt is None          return         fmt datetime   dt strftime   Y- m- dT H  M  S       tz   dt utcoffset       if tz is None          fmt timezone     00 00      else          fmt timezone   str format   0  06 2f    float tz total seconds     3600        return fmt datetime   fmt timezone

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Local to ISO nbsp 8601   import datetime datetime datetime now   isoformat    gt  gt  gt  2020-03-20T14 28 23 382748   UTC to ISO nbsp 8601   import datetime datetime datetime utcnow   isoformat    gt  gt  gt  2020-03-20T01 30 08 180856   Local to ISO nbsp 8601 without microsecond   import datetime datetime datetime now   replace microsecond 0  isoformat    gt  gt  gt  2020-03-20T14 30 43   UTC to ISO nbsp 8601 with TimeZone information  Python nbsp 3    import datetime datetime datetime utcnow   replace tzinfo datetime timezone utc  isoformat    gt  gt  gt  2020-03-20T01 31 12 467113 00 00   UTC to ISO nbsp 8601 with Local TimeZone information without microsecond  Python nbsp 3    import datetime datetime datetime now   astimezone   replace microsecond 0  isoformat    gt  gt  gt  2020-03-20T14 31 43 13 00   Local to ISO nbsp 8601 with TimeZone information  Python nbsp 3    import datetime datetime datetime now   astimezone   isoformat    gt  gt  gt  2020-03-20T14 32 16 458361 13 00   Notice there is a bug when using astimezone   on utc time  This gives an incorrect result   datetime datetime utcnow   astimezone   isoformat    Incorrect result   For Python 2  see and use pytz

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I agree with Jarek  and I furthermore note that the ISO offset separator character is a colon  so I think the final answer should be   isodate datetime isoformat datetime datetime now      str format   0  06 2f    -float time timezone    3600  replace

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I found the datetime isoformat in the documentation  It seems to do what you want   datetime isoformat  sep    Return a string representing the date and time in ISO 8601 format  YYYY-MM-DDTHH MM SS mmmmmm or  if microsecond is 0  YYYY-MM-DDTHH MM SS  If utcoffset   does not return None  a 6-character string is appended  giving the UTC offset in  signed  hours and minutes  YYYY-MM-DDTHH MM SS mmmmmm HH MM or  if microsecond is 0 YYYY-MM-DDTHH MM SS HH MM  The optional argument sep  default  T   is a one-character separator  placed between the date and time portions of the result  For example   gt  gt  gt    gt  gt  gt  from datetime import tzinfo  timedelta  datetime  gt  gt  gt  class TZ tzinfo           def utcoffset self  dt   return timedelta minutes -399       gt  gt  gt  datetime 2002  12  25  tzinfo TZ    isoformat       2002-12-25 00 00 00-06 39

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Adding a small variation to estani s excellent answer  Local to ISO 8601 with TimeZone and no microsecond info  Python 3    import datetime  time  utc offset sec   time altzone if time localtime   tm isdst else time timezone utc offset   datetime timedelta seconds -utc offset sec  datetime datetime now   replace microsecond 0  tzinfo datetime timezone offset utc offset   isoformat     Sample Output    2019-11-06T12 12 06-08 00    Tested that this output can be parsed by both Javascript Date and C  DateTime DateTimeOffset

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Here is what I use to convert to the XSD datetime format   from datetime import datetime datetime now   replace microsecond 0  isoformat     You get your ISO string   I came across this question when looking for the XSD date time format  xs dateTime   I needed to remove the microseconds from isoformat

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Correct me if I m wrong  I m not   but the offset from UTC changes with daylight saving time  So you should use  tz   str format   0  06 2f    float time altzone    3600    I also believe that the sign should be different   tz   str format   0  06 2f    -float time altzone    3600    I could be wrong  but I don t think so

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You ll need to use os stat to get the file creation time and a combination of time strftime and time timezone for formatting    gt  gt  gt  import time  gt  gt  gt  import os  gt  gt  gt  t   os stat  C  Path To File txt   st ctime  gt  gt  gt  t   time localtime t   gt  gt  gt  formatted   time strftime   Y- m- d  H  M  S   t   gt  gt  gt  tz   str format   0  06 2f    float time timezone    3600   gt  gt  gt  final   formatted   tz  gt  gt  gt    gt  gt  gt  final  2008-11-24 14 46 08-02 00

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import datetime  time     def convert enddate to seconds self  ts          Takes ISO 8601 format string  and converts into epoch time          dt   datetime datetime strptime ts  -7    Y- m- dT H  M  S  f                     datetime timedelta hours int ts -5 -3                    minutes int ts -2     int ts -6 -5   1       seconds   time mktime dt timetuple      dt microsecond 1000000 0     return seconds    gt  gt  gt  import datetime  time  gt  gt  gt  ts    2012-09-30T15 31 50 262-08 00   gt  gt  gt  dt   datetime datetime strptime ts  -7    Y- m- dT H  M  S  f    datetime timedelta hours int ts -5 -3    minutes int ts -2     int ts -6 -5   1    gt  gt  gt  seconds   time mktime dt timetuple      dt microsecond 1000000 0  gt  gt  gt  seconds 1348990310 26

[python] ISO time (ISO 8601) in Python

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