How to convert integer into date object python?

This question is already answered, but for the benefit of others looking at this question I'd like to add the following suggestion: Instead of doing the slicing yourself as suggested in the accepted answer, you might also use strptime() which is (IMHO) easier to read and perhaps the preferred way to do this conversion.

import datetime
s = "20120213"
s_datetime = datetime.datetime.strptime(s, '%Y%m%d')

I would suggest the following simple approach for conversion:

from datetime import datetime, timedelta
s = "20120213"
# you could also import date instead of datetime and use that.
date = datetime(year=int(s[0:4]), month=int(s[4:6]), day=int(s[6:8]))

For adding/subtracting an arbitary amount of days (seconds work too btw.), you could do the following:

date += timedelta(days=10)
date -= timedelta(days=5)

And convert back using:

s = date.strftime("%Y%m%d")

To convert the integer to a string safely, use:

s = "{0:-08d}".format(i)

This ensures that your string is eight charecters long and left-padded with zeroes, even if the year is smaller than 1000 (negative years could become funny though).

Further reference: datetime objects, timedelta objects