[R] print format for difftime

[BXC (Bendix Carstensen)]

Has anyone written a function that will print a difftime in the form:

hh:mm:ss

or

yy-mm-dd hh:mm:ss

depending on the actual size.
(sloppy notation for months/minutes, but surely you get the point).

Bendix
----------------------
Bendix Carstensen
Senior Statistician
Steno Diabetes Center
Niels Steensens Vej 2
DK-2820 Gentofte
Denmark
tel: +45 44 43 87 38
mob: +45 30 75 87 38
fax: +45 44 43 07 06
bxc at steno.dk
www.biostat.ku.dk/~bxc