How to convert string in to date in Python

%Y is for full year
%y is the short version for year

Your code is totally fine, just change the year directive to lowercase %y will do.

import datetime
from datetime import datetime
dat="012915"
dat = datetime.strptime(dat, '%m%d%y').date()
dat

I think you are looking for

import datetime
from datetime import datetime
dat="012915"
#lower %y
dat = datetime.strptime(dat, '%m%d%y').date()
print(dat)

this will give you

2015-01-29

Trying this out; changing the format string to '%m%d%y' seems to work. Looking at the python docs:

%y Year without century as a zero-padded decimal number.

%Y Year with century as a decimal number.

So the first one is what you need. Source: https://docs.python.org/3/library/datetime.html#strftime-and-strptime-format-codes

import datetime
from datetime import datetime
dat="012915"
dat = datetime.strptime(dat, '%m%d%y').date()
print(dat)

Change %Y to %y. If you want to use %Y, change dat to '01292015'. y% is formatted as 15 while %Y is formatted as 2015.

from datetime import datetime
date_str = '012915'
date_obj = datetime.strptime(date_str, '%m/%d/%y')

print("The type of the date is now",  type(date_obj))
print("The date is", date_obj)