The format is a string using the following symbols:
Two digit hours
Two digit minutes
Seconds and fractions of a second, up to six decimal places. Not all platforms support timestamps to a precision of six places.
A.M. or P.M. (12 hour clock)—omit AA and PP for 24 hour time
PM if needed (12 hour clock)—omit AA and PP for 24 hour time
Each symbol is substituted with the appropriate data for the time that is being formatted. Any format symbol that represents
character rather than digit output can be put in uppercase, which causes the substituted characters to also be in uppercase.
For numbers, using mixed case in the format string suppresses leading zeros.