Format string Meaning Sample output
o Round-trippable 2010-01-02T17:11:30.0000000
r, R RFC 1123 standard Sun, 02 Jan 2000 17:11:30 GMT
s Sortable; ISO 8601 2010-01-02T17:11:30
u "Universal" Sortable 2010-01-02 17:11:30Z
U UTC Sunday, 02 January 2000 08:11:30