Develop Reference

Time value does not match the format. ValueError in python

I am trying to convert a string to datetime object using the strptime function.
I am encountering a ValueError that says format doesn't match, so I did double checking and confirmed that the format in the string matches the format I am passing as the parameter for strptime.
I have also referenced this question: time data does not match format but there the month and year were swapped.
So does this only work with the '%y-%m-%d %H:%M:%S' format or is it dynamic as per the user input like in my case '%y-%m-%d-%H:%M:%S' ?
input:-
from datetime import datetime
stg = "2022-10-31-01:17:46"
do = datetime.strptime(stg, '%y-%m-%d-%H:%M:%S')
output
ValueError: time data '2022-09-31-01:17:46' does not match format '%y-%m-%d-%H:%M:%S'
Expected output:
#while printing 'do'
2020-09-31-01:17:46

You're almost there. You need %Y instead of %y since you're providing the year with the century (2022 instead of 22).
Your code would be
from datetime import datetime
stg = "2022-10-31-01:17:46"
do = datetime.strptime(stg, '%Y-%m-%d-%H:%M:%S')

Python - Converting string to datetime object

I've been trying to convert a timestamp that is a string to a datetime object. The problem is the timestamps formatting. I haven't been able to properly parse the timestamp using datetime.datetime.strptime. I could write my own little parser as its a simple problem but I was hoping to use strptime function, I just need help on the formatting.
Example
import datetime
formater = "%y-%m-%dT%H:%M:%SZ"
str_timestamp = "2021-03-13T18:27:37.60918Z"
timestamp = datetime.datetime.strptime(str_timestamp, formater)
print (timestamp)
Output
builtins.ValueError: time data '2021-03-13T18:27:37.60918Z' does not match format '%y-%m-%dT%H:%M:%SZ'
I'm clearly not symbolizing the formatter properly, the T and Z parts are what I can't account for.

y should be Y. y is for 2 digits year.
You should also take care for the milliseconds with .%f:
%Y-%m-%dT%H:%M:%S.%fZ

This format works:
formater = "%Y-%m-%dT%H:%M:%S.%fZ"
output:
2021-03-13 18:27:37.609180

convert date in one format to another format

I have a date in the format '%Y-%M-%d' for example '2017-08-01', that I'd like to convert to the format '%m-%d-%y' for example '8-1-2017'.
Only relevant examples I've found have been in php unfortunately.

from datetime import datetime
datetime.strptime("2017-08-01", '%Y-%m-%d').strftime('%m-%d-%y')
datetime.strptime("2017-08-01", '%Y-%m-%d')
#output
datetime.datetime(2017, 8, 1, 0, 0)
#output final
'08-01-17'
In the first part strptime , you are defining how the date is to you. In other words, you are turning your string into a datetime type instance. Then in the second part strftime you are formatting it the way you wish it to be.
Official definitions
date, datetime, and time objects all support a strftime(format) method,
to create a string representing the time under the control of an explicit format string.
Conversely, the datetime.strptime() class method creates
a datetime object from a string representing a date and
time and a corresponding format string.

problem of date conversion from english to french

I try to convert a date in english (2019-10-07) in french (07/10/2016)
I try
dat = '07/10/2019'
dat = time.strftime('%Y-%m-%d')
but got the result '2019-10-16' instead of '2019-10-07'

using datetime you can decide the format in which the source date is provided, and the target format you want.
from datetime import datetime
dat = '07/10/2019'
datetime.strptime(dat, "%d/%m/%Y").strftime("%Y-%m-%d")
out[6]: '2019-10-07'

strftime needs a time/date to convert, and it will use the current date and time if you don't provide one. The previous value of dat is not relevant - this information is not seen by strftime.
You need to provide the time information that strftime will format, as a tuple that you can get by parsing the original string. For this, use strptime (f for format, p for parse).
So:
dmy = '07/10/2019'
ymd = time.strftime('%Y-%m-%d', time.strptime(dmy, '%d/%m/%Y'))
# ^^^^^^^^ ^^^^^^^^
# output schema input schema
# now ymd is '2019-10-07'
(Or you can use the datetime module as in the other answer. This way, the parsing gives you an object, which has a method to format back - so you can write the whole operation "in order" on the line. But the general principle is the same: you need to parse, then format, and you need to specify the schema on each side.)

with :
dat = time.strftime('%Y-%m-%d')
you recover your actual date.
you need to make :
from datetime import datetime
dat = '07/10/2019'
dat = datetime.strptime(dat, '%m/%d/%Y')
print(dat.strftime('%Y-%m-%d') )

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.