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 in the format -HHMM.

%Z

timezone name

For LocalTime (and ZonedTime and UTCTime and UniversalTime):

%c

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

For TimeOfDay (and LocalTime and ZonedTime and UTCTime and UniversalTime):

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

%p

day-half of day from (amPm locale), AM, PM

%H

hour of day (24-hour), 0-padded to two chars, 00 - 23

%k

hour of day (24-hour), space-padded to two chars, 0 - 23

%I

hour of day-half (12-hour), 0-padded to two chars, 01 - 12

%l

hour of day-half (12-hour), space-padded to two chars, 1 - 12

%M

minute of hour, 0-padded to two chars, 00 - 59

%S

second of minute (without decimal part), 0-padded to two chars, 00 - 60

%q

picosecond of second, 0-padded to twelve chars, 000000000000 - 999999999999.

%Q

decimal point and fraction of second, 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 and UniversalTime):

%D

same as %m/%d/%y

%F

same as %Y-%m-%d

%x

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

%Y

year, no padding. Note %0Y and %_Y pad to four chars

%y

year of century, 0-padded to two chars, 00 - 99

%C

century, no padding. Note %0C and %_C pad to two chars

%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, 0-padded to two chars, 01 - 12

%d

day of month, 0-padded to two chars, 01 - 31

%e

day of month, space-padded to two chars, 1 - 31

%j

day of year, 0-padded to three chars, 001 - 366

%G

year for Week Date format, no padding. Note %0G and %_G pad to four chars

%g

year of century for Week Date format, 0-padded to two chars, 00 - 99

%f

century for Week Date format, no padding. Note %0f and %_f pad to two chars

%V

week of year for Week Date format, 0-padded to two chars, 01 - 53

%u

day of week 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 of year where weeks start on Sunday (as sundayStartWeek), 0-padded to two chars, 00 - 53

%w

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

%W

week of year where weeks start on Monday (as mondayStartWeek), 0-padded to two chars, 00 - 53

Parses a time value given a format string. Supports the same %-codes as formatTime, including %-, %_ and %0 modifiers. Case is not significant. Some variations in the input are accepted:

%z

accepts any of -HHMM or -HH:MM.

%Z

accepts any string of letters, or any of the formats accepted by %z.

%0Y

accepts exactly four digits.

%0G

accepts exactly four digits.

%0C

accepts exactly two digits.

%0f

accepts exactly two digits.

Parse a time value given a format string. Fails if the input could not be parsed using the given format. See parseTimeM for details.

Parse a time value given a format string. See parseTimeM for details.

Parse a time value given a format string. See parseTimeM for details.

The class of types which can be parsed given a UNIX-style time format string.

Locale representing American usage.

knownTimeZones contains only the ten time-zones mentioned in RFC 822 sec. 5: "UT", "GMT", "EST", "EDT", "CST", "CDT", "MST", "MDT", "PST", "PDT". Note that the parsing functions will regardless parse single-letter military time-zones and +HHMM format.

Construct format string according to ISO-8601.

The Maybe String argument allows to supply an optional time specification. E.g.:

iso8601DateFormat Nothing            == "%Y-%m-%d"           -- i.e. YYYY-MM-DD
iso8601DateFormat (Just "%H:%M:%S")  == "%Y-%m-%dT%H:%M:%S"  -- i.e. YYYY-MM-DDTHH:MM:SS

Format string according to RFC822.