Date formats

[mike milliger]

I read the documentation in the Python Reference Library (6.3) on time
access and conversions and chapter 8 in programming python, yet I can't
figure out if i need ( or how to use) a tuple to format the return from
localtime().  i get a string now (wed jun 10 1999 xx:xx:xx) but i need
to format it to yyyymmdd_hhmmss.  Is there any switch ( %) or function
that can be useful?  Any help is appreciated.
--mike