Converting week numbers to dates

Here is some python code I adapted from this stackoverflow post to get the first day of a week specificed by a week number. This method includes leap year and summer time differences.

import time
def weeknum(num,year):
	instr = str(year)+" "+str(num-1)+" 1"
	print time.asctime(time.strptime(instr,'%Y %W %w'))

Here is me exectuting the code in Python’s IDLE shell:

See that the first week of 2009 actually started in 2008, but by the end of that week we are in 2009.