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Subtracting datetime in string format with datetime format

I have 2 variables.
One is datetime in string format and the other is datetime in datetime.datetime format.
For example -
2021-09-06T07:58:19.032Z # string
2021-09-05 14:58:10.209675 # datetime.datetime
I want to find out the difference between these 2 times in seconds.
I think we need to have both in datetime before we can do this subtraction.
I'm having a hard time converting the string to datetime.
Can someone please help.

You can convert the string into datetime object with strptime()
An example with your given dates:
from datetime import datetime
# Assuming this is already a datetime object in your code, you don't need this part
# I needed this part to be able to use it as a datetime object
date1 = datetime.strptime("2021-09-05 14:58:10.209675", "%Y-%m-%d %H:%M:%S.%f")
## The part where the string is converted to datetime object
# Since the string has "T" and "Z", we will have to remove them before we convert
formatted = "2021-09-06T07:58:19.032Z".replace("T", " ").replace("Z", "")
>>> 2021-09-06 07:58:19.032
# Finally, converting the string
date2 = datetime.strptime(formatted, "%Y-%m-%d %H:%M:%S.%f")
# Now date2 variable is a datetime object
# Performing a simple operation
print(date1 - date2)
>>> -1 day, 6:59:51.177675

Convert the str to datetime via strptime() and then get the difference of the 2 datetime objects in seconds via total_seconds().
from datetime import datetime, timezone
# Input
dt1_str = "2021-09-06T07:58:19.032Z" # String type
dt2 = datetime(year=2021, month=9, day=5, hour=14, minute=58, second=10, microsecond=209675, tzinfo=timezone.utc) # datetime type
# Convert the string to datetime
dt1 = datetime.strptime(dt1_str, "%Y-%m-%dT%H:%M:%S.%f%z")
# Subtract the datetime objects and get the seconds
diff_seconds = (dt1 - dt2).total_seconds()
print(diff_seconds)
Output
61208.822325

The first string time you mention could be rfc3339 format.
A module called python-dateutil could help
import dateutil.parser
dateutil.parser.parse('2021-09-06T07:58:19.032Z')
datetime module could parse this time format by
datetime.datetime.strptime("2021-09-06T07:58:19.032Z","%Y-%m-%dT%H:%M:%S.%fZ")
But this way may cause trouble when get a time in another timezone because it doesn't support timezone offset.

Convert Timestamp to ISO Date

I am extracting Data from Mongodb using some date filter. In mongo my date is in ISO format . As i am dynamically adding date from some variable which is in timestamp format(2019-07-15 14:54:53).Getting Empty Result
curs = col1.aggregate([{'$match':{update_col: {'$gte': last_updt }}},{'$project':json_acceptable_string}])
I am expecting Rows after filtering but acual its giving empty dataset

you can use datetime.strptime to parse the original string to a datetime object, then use datetime.isoformat to get it in ISO format.
try this:
import datetime
original_date = '2019-07-15 14:54:53'
date_obj = datetime.datetime.strptime(original_date, "%Y-%m-%d %H:%M:%S")
iso_date = date_obj.isoformat()
print(iso_date)

try this
from dateutil import parser as date_parser
dt_obj = date_parser.parse('2019-07-15 14:54:53')
where dt_obj is an object of standard datetime.datetime class

You can use fromisoformat.
Try
from datetime import datetime
iso_string = '2019-07-15 14:54:53'
you_date_obj = datetime.fromisoformat(iso_string)

Convert a epoch timestamp to yyyy/mm/dd hh:mm

I'm given a timestamp (time since the epoch) and I need to convert it into this format:
yyyy/mm/dd hh:mm
I looked around and it seems like everyone else is doing this the other way around (date to timestamp).
If your answer involves dateutil that would be great.

Using datetime instead of dateutil:
import datetime as dt
dt.datetime.utcfromtimestamp(seconds_since_epoch).strftime("%Y/%m/%d %H:%M")
An example:
import time
import datetime as dt
epoch_now = time.time()
sys.stdout.write(str(epoch_now))
>>> 1470841955.88
frmt_date = dt.datetime.utcfromtimestamp(epoch_now).strftime("%Y/%m/%d %H:%M")
sys.stdout.write(frmt_date)
>>> 2016/08/10 15:09
EDIT: strftime() used, as the comments suggested.

'datetime.datetime' object has no attribute 'read'

Users in my app have date_joined fields that are in this format: 2014-12-14 14:46:43.379518+00:00
In order to pass this datetime along to Intercom.io, it must be a UNIX timestamp like this: 1426020706 (this is not the same time, just an example).
I've tried several methods I've read here on Stack Overflow (nothing in this question has the same starting time format: Converting datetime.date to UTC timestamp in Python), but none have worked. mktime() seemed promising, but I got "'datetime.datetime' object has no attribute 'mktime'."
I just tried this:
import time
import dateutil.parser
import member.models import Member
member = Member.objects.get(email="aspeksnijder#outlook.com")
date_joined = member.date_joined
dt = dateutil.parser.parse(date_joined)
print int(time.mktime(dt.timetuple()))
It returned "'datetime.datetime' object has no attribute 'read'". How can I accomplish this?

It seems you have an aware datetime object. If you print it then it looks like:
2014-12-14 14:46:43.379518+00:00
To be sure print(repr(date_joined)).
Converting datetime.date to UTC timestamp in Python shows several ways how you could get the timestamp e.g.,
timestamp = date_joined.timestamp() # in Python 3.3+
Or on older Python versions:
from datetime import datetime
# local time = utc time + utc offset
utc_naive = date_joined.replace(tzinfo=None) - date_joined.utcoffset()
timestamp = (utc_naive - datetime(1970, 1, 1)).total_seconds()
Note: timestamp = calendar.timegm(date_joined.utctimetuple()) would also work in your case but it may return a wrong result silently if you pass it a naive datetime object that represents local time by mistake.
If your input is a time string then convert the time string into a datetime object first.

What about (using the dateutil and pytz packages):
import dateutil.parser
from datetime import datetime
import calendar
import pytz
def str2ts(s):
''' Turns a string into a non-naive datetime object, then get the timestamp '''
# However you get from your string to datetime.datetime object
dt = dateutil.parser.parse(s) # String to non-naive datetime
dt = pytz.utc.normalize(dt) # Normalize datetime to UTC
ts = calendar.timegm(dt.timetuple()) # Convert UTC datetime to UTC timestamp
return int(ts)
def ts2str(ts):
'''Convert a UTC timestamp into a UTC datetime, then format it to a string'''
dt = datetime.utcfromtimestamp(ts) # Convert a UTC timestamp to a naive datetime object
dt = dt.replace(tzinfo=pytz.utc) # Convert naive datetime to non-naive
return dt.strftime('%Y-%m-%d %H:%M:%S.%f%z')
Which we can test with:
# A list of strings corresponding to the same time, with different timezone offsets
ss = [
'2014-12-14 14:46:43.379518+00:00',
'2014-12-14 15:46:43.379518+01:00',
'2014-12-14 16:46:43.379518+02:00',
'2014-12-14 17:46:43.379518+03:00',
]
for s in ss:
ts = str2ts(s)
s2 = ts2str(ts)
print ts, s2
Output:
1418568403 2014-12-14 14:46:43.000000+0000
1418568403 2014-12-14 14:46:43.000000+0000
1418568403 2014-12-14 14:46:43.000000+0000
1418568403 2014-12-14 14:46:43.000000+0000
These output all the same timestamps, and "verification" formatted strings.

You can try the following Python 3 code:
import time, datetime
print(time.mktime(datetime.datetime.strptime("2014-12-14 14:46:43.379518", '%Y-%m-%d %H:%M:%S.%f').replace(tzinfo=datetime.timezone.utc).timetuple()))
which prints:
1418568403.0

I had that problem when I used input from Django's DateField, which is displayed in a form of XXXX-YY-ZZ: parse(django_datefield) causes the exception.
The solution: use str(django_datefield).
parse(str(django_datefield))

I know this is an old post, but I want to highlight that the answer is likely what #Peter said in his comment:
It looks like member.date_joined is already a datetime object, and there's no need to parse it. – Peter Feb 25 '17 at 0:33
So-- your model probably already parses into a datetime.datetime object for you.

how to subtract date from date from sql in python

I run a sql query that returns a date in the format '2015-03-01T17:09:00.000+0000' I want to subtract this from today's date.
I am getting today's date with the following:
import datetime
now = datetime.datetime.now()
The formats don't seem to line up and I can't figure out a standardize format.

You can use strptime from datetime module to get python compatible date time from your query result using a format string. (You might have to play with the format string a bit to suit your case)
ts = '2015-03-01T17:09:00.000+0000' to a format string like
f = '%Y-%m-%dT%H:%M:%S.%f%z'
date_from_sql = datetime.datetime.strptime(ts, f)
now = datetime.datetime.now()
delta = date_from_sql - now
The .000 is probably microseconds (denoted by %f in the format string) and the +0000 is the utc offset (denoted by %z in the format string). Check this out for more formatting options: https://docs.python.org/2/library/datetime.html#strftime-strptime-behavior
Check out this thread for an example: what is the proper way to convert between mysql datetime and python timestamp?
Checkout this for more on strptime https://docs.python.org/2/library/datetime.html#datetime.datetime.strptime

Getting the delta between two datetime objects in Python is really simple, you simply subtract them.
import datetime
d1 = datetime.datetime.now()
d2 = datetime.datetime.now()
delta = d2 - d1
print delta.total_seconds()
d2 - d1 returns a datetime.timedelta object, from which you can get the total second difference between the two dates.
As for formatting the dates, you can read about formatting strings into datetime objects, and datetime objects into string here
You'll read about the strftime() and strptime() functions, and with them you can get yourself two datetime objects which you can subtract from each other.