Reformatting Dates Python - python

I have a file with dates in a few different formats and am trying to get them all into YYYYMMDD format in Python. Most of the dates are in the below format:
Mon, 01 Jul 2013 16:33:59 GMT
and I have no idea how to get them into
20130701
I apologize if this is a pretty simple question---I am sort of new to python
EDIT: I am trying to do this for ANY given date. I used the 01 July as an example and in retrospect made it seem like I was asking a different question. So I guess I am looking for something that can both find dates and reformat them

Use the python-dateutil library:
from dateutil import parser
dtobject = parser.parse(datestring)
The datutil.parser.parse() method recognises a wide variety of date formats, and returns a datetime.datetime() object.
Use the datetime.strftime() method if you want to format the result as a (uniform) string again:
dtobject.strftime('%Y%m%d')
Demo:
>>> from dateutil import parser
>>> parser.parse('Mon, 01 Jul 2013 16:33:59 GMT')
datetime.datetime(2013, 7, 1, 16, 33, 59, tzinfo=tzlocal())
>>> parser.parse('Mon, 01 Jul 2013 16:33:59 GMT').strftime('%Y%m%d')
'20130701'

This can be achieved following way also:
import datetime
x = 'Mon, 01 Jul 2013 16:33:59 GMT'
''.join(str(datetime.datetime.strptime(x, '%a, %d %b %Y %H:%M:%S %Z').date()).split('-'))
if any other parameter is introduced in your date string, you can include the directive . for example %p is Locale’s equivalent of either AM or PM.

Related

normalize different date formats

I am trying to work with an XML data that has different kinds of (string) date values, like:
'Sun, 04 Apr 2021 13:32:26 +0200'
'Sun, 04 Apr 2021 11:52:29 GMT'
I want to save these in a Django object that has a datetime field.
The script that I have written to convert a str datetime is as below:
def normalise(val):
val = datetime.strptime(val, '%a, %d %b %Y %H:%M:%S %z')
return val
Although, this does not work for every datetime value I scrape. For example for above 2 examples, the script works for the first one but crashes for the second.
What would be an ideal way of normalising all the datetime values ?
dateutil module parses many different types of formats. You can find the doc here
This is a simple example:
if __name__ == '__main__':
from dateutil.parser import parse
date_strs = ['Sun, 04 Apr 2021 13:32:26 +0200','Sun, 04 Apr 2021 11:52:29 GMT']
for d in date_strs:
print(parse(d))
output:
2021-04-04 13:32:26+02:00
2021-04-04 11:52:29+00:00
If there are other date formats that this doesn't cover you can to store specific python format strings keyed by the xml element name.

Python 3.7: converting a string with different timezone into date

I am trying to convert a string into date format in Python.
I am using following statement
datetime_obj = datetime.datetime.strptime("Sun Aug 19 16:24:31 PDT 2018", "%a %b %d %H:%M:%S %Z %Y")
However, I get an error -
ValueError: time data 'Sun Aug 19 16:24:31 PDT 2018' does not match format '%a %b %d %H:%M:%S %Z %Y'
If I remove the timezone from the date string and the format string, the code works perfect. Which leads me to believe that the issue is related to the timezone but I am not sure what actions should be taken.
I am in eastern timezone and the time zone in the string is in Pacific timezone.
Appreciate any help on this.
As mentioned in this answer you can use python-dateutil for this:
>>> from dateutil import parser
>>> datetime_obj = parser.parse("Sun Aug 19 16:24:31 PDT 2018")
datetime.datetime(2018, 8, 19, 16, 24, 31)
Standard datetime module behaves very strangely with parsing timezones, as I see reading this answer in question related to similar problem.

How to convert GMT time to string time

How to convert GMT time to string time? it's quite strange, when I print the time in back-end, the time is in string time format, but when I transfer it to the front-end via JSON file, the time has changed to GMT format. Why? Could someone help me?
Input: Wed, 25 Jul 2018 19:19:42 GMT
Output: 2018-07-25 19:19:42
When you convert the original time to JSON Format, it will be changed to GMT Time format. To solve this problem, you can change the time to string before converting it to JSON.
You could do something like -
from datetime import datetime
ip = 'Wed, 25 Jul 2018 19:19:42 GMT'
op = datetime.strftime(datetime.strptime(ip,'%a, %d %b %Y %H:%M:%S %Z'), '%Y-%m-%d %H:%M:%S')
# op 2018-07-25 19:19:42
Refer to this beautiful table here to get the formats right and then look into strftime and strptime
You can find resources here on strptime
from datetime import datetime
t = 'Wed, 25 Jul 2018 19:19:42 GMT'
datetime.strptime(t,'%a, %d %b %Y %H:%M:%S %Z')
datetime.datetime(2018, 7, 25, 19, 19, 42)

How to get the datetime from a string containing '2nd' for the date in Python?

I've got a couple strings from which I want to get the datetime. They are formatted like this:
Thu 2nd May 2013 19:00
I know almost how I can convert this to a datetime, except for that I'm having trouble with the "2nd". I now have the following
>>> datetime.strptime('Thu 02 May 2013 19:00', '%a %d %B %Y %H:%M')
datetime.datetime(2013, 5, 2, 19, 0)
which works fine with a zero padded number for the day of the month, but when I try the 2nd, it gives a ValueError:
>>> datetime.strptime('Thu 2nd May 2013 19:00', '%a %d %B %Y %H:%M')
Traceback (most recent call last):
File "<input>", line 1, in <module>
(data_string, format))
ValueError: time data 'Thu 2nd May 2013 19:00' does not match format '%a %d %B %Y %H:%M'
In the list of datetime directives I can't find anything relating to ordered values (1st, 2nd, 3rd etc) for dates. Does anybody know how I can get this to work? All tips are welcome!
Consider using dateutil.parser.parse.
It's a third party library that has a powerful parser which can handle these kinds of things.
from dateutil.parser import parse
s = 'Thu 2nd May 2013 19:00'
d = parse(s)
print(d, type(d))
# 2013-05-02 19:00:00 <class 'datetime.datetime'>
A brief caveat (doesn't really occur in your case): if dateutil can't find an aspect of your date in the string (say you leave out the month) then it will default to the default argument. This defaults to the current date with the time 00:00:00. You can obviously over-write this if necessary with a different datetime object.
The easiest way to install dateutil is probably using pip with the command pip install python-dateutil.
You can preparse the original string to adjust the day to be suitable for your strptime, eg:
from datetime import datetime
import re
s = 'Thu 2nd May 2013 19:00'
amended = re.sub('\d+(st|nd|rd|th)', lambda m: m.group()[:-2].zfill(2), s)
# Thu 02 May 2013 19:00
dt = datetime.strptime(amended, '%a %d %B %Y %H:%M')
# 2013-05-02 19:00:00
It's straightforward to remove the suffix from the date without using regular expressions or an external library.
def remove_date_suffix(s):
parts = s.split()
parts[1] = parts[1].strip("stndrh") # remove 'st', 'nd', 'rd', ...
return " ".join(parts)
Then it's as simple as using strptime as you'd expect:
>>> s = "Thu 2nd May 2013 19:00"
>>> remove_date_suffix(s)
'Thu 2 May 2013 19:00'
>>> datetime.strptime(remove_date_suffix(s), '%a %d %B %Y %H:%M')
datetime.datetime(2013, 5, 2, 19, 0)
import re
from datetime import datetime
def proc_date(x):
return re.sub(r"\b([0123]?[0-9])(st|th|nd|rd)\b",r"\1",x)
>>> x='Thu 2nd May 2013 19:00'
>>> proc_date(x)
'Thu 2 May 2013 19:00'
>>> datetime.strptime(proc_date(x), '%a %d %B %Y %H:%M')
datetime.datetime(2013, 5, 2, 19, 0)

Parse date/time from a string

I'm using Python 3.3. I'm getting an email from an IMAP server, then converting it to an instance of an email from the standard email library.
I do this:
message.get("date")
Which gives me this for example:
Wed, 23 Jan 2011 12:03:11 -0700
I want to convert this to something I can put into time.strftime() so I can format it nicely. I want the result in local time, not UTC.
There are so many functions, deprecated approaches and side cases, not sure what is the modern route to take?
Something like this?
>>> import time
>>> s = "Wed, 23 Jan 2011 12:03:11 -0700"
>>> newtime = time.strptime(s, '%a, %d %b %Y %H:%M:%S -0700')
>>> print(time.strftime('Two years ago was %Y', newtime))
Two years ago was 2011 # Or whatever output you wish to receive.
I use python-dateutil for parsing datetime strings. Function parse from this library is very handy for this kind of task
Do this:
import email, email.utils, datetime, time
def dtFormat(s):
dt = email.utils.parsedate_tz(s)
dt = email.utils.mktime_tz(dt)
dt = datetime.datetime.fromtimestamp(dt)
dt = dt.timetuple()
return dt
then this:
s = message.get("date") # e.g. "Wed, 23 Jan 2011 12:03:11 -0700"
print(time.strftime("%Y-%m-%d-%H-%M-%S", dtFormat(s)))
gives this:
2011-01-23-21-03-11

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