Substitute various time-related information for each %-code in the string, as per formatCharacter.

For all types (note these three are done here, not by formatCharacter):

%%

%

%t

tab

%n

newline

glibc-style modifiers can be used before the letter (here marked as z):

%-z

no padding

%_z

pad with spaces

%0z

pad with zeros

%^z

convert to upper case

%#z

convert to lower case (consistently, unlike glibc)

For TimeZone (and ZonedTime and UTCTime):

%z

timezone offset on the format -HHMM.

%Z

timezone name

For LocalTime (and ZonedTime and UTCTime):

%c

as dateTimeFmt locale (e.g. %a %b %e %H:%M:%S %Z %Y)

For TimeOfDay (and LocalTime and ZonedTime and UTCTime):

%R

same as %H:%M

%T

same as %H:%M:%S

%X

as timeFmt locale (e.g. %H:%M:%S)

%r

as time12Fmt locale (e.g. %I:%M:%S %p)

%P

day half from (amPm locale), converted to lowercase, am, pm

%p

day half from (amPm locale), AM, PM

%H

hour, 24-hour, leading 0 as needed, 00 - 23

%I

hour, 12-hour, leading 0 as needed, 01 - 12

%k

hour, 24-hour, leading space as needed, 0 - 23

%l

hour, 12-hour, leading space as needed, 1 - 12

%M

minute, 00 - 59

%S

second, without decimal part, 00 - 60

%q

picosecond, including trailing zeros, 000000000000 - 999999999999.

%Q

decimal point and up to 12 second decimals, without trailing zeros. For a whole number of seconds, %Q produces the empty string.

For UTCTime and ZonedTime:

%s

number of whole seconds since the Unix epoch. For times before the Unix epoch, this is a negative number. Note that in %s.%q and %s%Q the decimals are positive, not negative. For example, 0.9 seconds before the Unix epoch is formatted as -1.1 with %s%Q.

For Day (and LocalTime and ZonedTime and UTCTime):

%D

same as %m/%d/%y

%F

same as %Y-%m-%d

%x

as dateFmt locale (e.g. %m/%d/%y)

%Y

year

%y

last two digits of year, 00 - 99

%C

century (being the first two digits of the year), 00 - 99

%B

month name, long form (fst from months locale), January - December

%b, %h

month name, short form (snd from months locale), Jan - Dec

%m

month of year, leading 0 as needed, 01 - 12

%d

day of month, leading 0 as needed, 01 - 31

%e

day of month, leading space as needed, 1 - 31

%j

day of year for Ordinal Date format, 001 - 366

%G

year for Week Date format

%g

last two digits of year for Week Date format, 00 - 99

%f

century (first two digits of year) for Week Date format, 00 - 99

%V

week for Week Date format, 01 - 53

%u

day for Week Date format, 1 - 7

%a

day of week, short form (snd from wDays locale), Sun - Sat

%A

day of week, long form (fst from wDays locale), Sunday - Saturday

%U

week number of year, where weeks start on Sunday (as sundayStartWeek), 00 - 53

%w

day of week number, 0 (= Sunday) - 6 (= Saturday)

%W

week number of year, where weeks start on Monday (as mondayStartWeek), 00 - 53