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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')

How to convert the string to date time format?

I have the following string 20211208_104755, representing date_time format. I want to convert it to the python datetime format using datetime.strip() method.
mydatetime = "20211208_104755"
datetime_object = datetime.strptime(mydatetime, '%y/%m/%d')
However I am getting the following error.
ValueError: time data '20211208' does not match format '%y/%m/%d'

The second argument in strptime has to match the pattern of your datetime string. You can find the patterns and their meaning on https://docs.python.org/3/library/datetime.html
In your case, you can format it as
from datetime import datetime
mydatetime = "20211208_104755"
datetime_object = datetime.strptime(mydatetime, '%Y%m%d_%H%M%S')
print(datetime_object)
>>> 2021-12-08 10:47:55

what should work is to define how the mydatetime string is composed.
example:
%Y is the year (4 digits); check here for format (section strftime() Date Format Codes)
So in your example I would assume it's like this:
mydatetime = "20211208_104755"
datetime_object = datetime.strptime(mydatetime, '%Y%m%d_%H%M%S')
print (datetime_object)
result
2021-12-08 10:47:55
and
type(datetime_object)
datetime.datetime

Get YYYY-DD-MM from YYYY-DD-MM HH:MM:SS

I have a date in the format 2012-01-01 06:00:00. I want to get only the date in the format 2012-01-01.
I've tried multiple links such as Converting (YYYY-MM-DD-HH:MM:SS) date time
But, I could not find the solution.

Parse. str -> date.
from datetime import datetime
s = "2012-01-01 06:00:00"
dt = datetime.strptime(s, "%Y-%m-%d %H:%M:%S")
Format. date -> str.
s_ymd = dt.strftime("%Y-%m-%d")
Result:
>>> s_ymd
'2012-01-01'

Assuming your date is a string, the following works fine:
str = "2012-01-01 06:00:00"
print(str[:10])
The notation [:10] basically means "take first 10 characters of the string".

Converting string to datetime with milliseconds and timezone - Python

I have the following python snippet:
from datetime import datetime
timestamp = '05/Jan/2015:17:47:59:000-0800'
datetime_object = datetime.strptime(timestamp, '%d/%m/%y:%H:%M:%S:%f-%Z')
print datetime_object
However when I execute the code, I'm getting the following error:
ValueError: time data '05/Jan/2015:17:47:59:000-0800' does not match format '%d/%m/%y:%H:%M:%S:%f-%Z'
what's wrong with my matching expression?

EDIT 2: According to this post, strptime doesn't support %z (despite what the documentation suggests). To get around this, you can just ignore the timezone adjustment?:
from datetime import datetime
timestamp = '05/Jan/2015:17:47:59:000-0800'
# only take the first 24 characters of `timestamp` by using [:24]
dt_object = datetime.strptime(timestamp[:24], '%d/%b/%Y:%H:%M:%S:%f')
print(dt_object)
Gives the following output:
$ python date.py
2015-01-05 17:47:59
EDIT: Your datetime.strptime argument should be '%d/%b/%Y:%H:%M:%S:%f-%z'
With strptime(), %y refers to
Year without century as a zero-padded decimal number
I.e. 01, 99, etc.
If you want to use the full 4-digit year, you need to use %Y
Similarly, if you want to use the 3-letter month, you need to use %b, not %m
I haven't looked at the rest of the string, but there are possibly more mismatches. You can find out how each section can be defined in the table at https://docs.python.org/2/library/datetime.html#strftime-and-strptime-behavior

And UTC offset is lowercase z.

Comparing two dates in different format with python

I have 2 dates defined as a strings. If I would know the original date format, I would compare it like this:
import time
date1 = "1/1/2013 12:00:00 AM" # formatted like "%m/%d/%Y %H:%M:%S %p"
date2 = "1/1/2016" # formatted like "%m/%d/%Y"
format1 = "%m/%d/%Y %H:%M:%S %p"
format2 = "%m/%d/%Y"
if time.strptime(date1, format1) > time.strptime(date2, format2):
pass
How can I compare it if I do not know the date format?

How can I compare it if I do not know the date format?
You can't.
Every comparison assumes that you know what you are comparing.

You can try to parse it with dateutil.parser.parse. This method parse a string in one of the supported formats. And then compare it.
datautil is a third-party module.