Day-O

Date & Time Format Patterns

A date format pattern is a string of characters where specific strings of characters are replaced with date and time data from a calendar when formatting. The following are examples:

Pattern Result (in a particular locale)
yyyy.MM.dd G 'at' HH:mm:ss zzz 1996.07.10 AD at 15:08:56 PDT
EEE, MMM d, ''yy Wed, July 10, '96
h:mm a 12:08 PM
hh 'o''clock' a, zzzz 12 o'clock PM, Pacific Daylight Time
K:mm a, z 0:00 PM, PST
yyyyy.MMMM.dd GGG hh:mm aaa 01996.July.10 AD 12:08 PM

The Date Symbol Table below contains the characters used in patterns to show the appropriate formats for a given locale, such as yyyy for the year. Characters may be used multiple times. For example, if y is used for the year, yy might produce 99, whereas yyyy produces 1999. For most numerical fields, the number of characters specifies the field width. For example, if h is the hour, h might produce 5, but hh produces 05. For some characters, the count specifies whether an abbreviated or full form should be used, but may have other choices, as given below.

Two single quotes (eg. '') represents a literal single quote, either inside or outside single quotes. Text within single quotes is not interpreted in any way (eg. 'o''clock' is replaced with o'clock). Otherwise all ASCII letter from a-z and A-Z are reserved as syntax characters, and require quoting if they are to represent literal characters.

Date Symbol Table

Field Sym. No. Example Description
era G 1..3 AD Era - Replaced with the Era string for the current date. One to three letters for the abbreviated form, four letters for the long form, five for the narrow form.
4 Anno Domini
5 A
year y 1..n 1996 Year. Normally the length specifies the padding, but for two letters it also specifies the maximum length.
Y 1..n 1997 Year (in “Week of Year” based calendars). This year designation is used in ISO year-week calendar as defined by ISO 8601, but can be used in non-Gregorian based calendar systems where week date processing is desired. May not always be the same value as calendar year.
u 1..n 4601 Extended year. This is a single number designating the year of this calendar system, encompassing all supra-year fields. For example, for the Julian calendar system, year numbers are positive, with an era of BCE or CE. An extended year value for the Julian calendar system assigns positive values to CE years and negative values to BCE years, with 1 BCE being year 0.
quarter Q 1..2 02 Quarter - Use one or two for the numerical quarter, three for the abbreviation, or four for the full name.
3 Q2
4 2nd quarter
q 1..2 02 Stand-Alone Quarter - Use one or two for the numerical quarter, three for the abbreviation, or four for the full name.
3 Q2
4 2nd quarter
month M 1..2 09 Month - Use one or two for the numerical month, three for the abbreviation, or four for the full name, or five for the narrow name.
3 Sept
4 September
5 S
L 1..2 09 Stand-Alone Month - Use one or two for the numerical month, three for the abbreviation, or four for the full name, or five for the narrow name.
3 Sept
4 September
5 S
l 1 * Special symbol for Chinese leap month, used in combination with M. Only used with the Chinese calendar.
week w 1..2 27 Week of Year.
W 1 3 Week of Month
day d 1..2 1 Date - Day of the month
D 1..3 345 Day of year
F 1 2 Day of Week in Month. The example is for the 2nd Wed in July
g 1..n 2451334 Modified Julian day. This is different from the conventional Julian day number in two regards. First, it demarcates days at local zone midnight, rather than noon GMT. Second, it is a local number; that is, it depends on the local time zone. It can be thought of as a single number that encompasses all the date-related fields.
week day E 1..3 Tues Day of week - Use one through three letters for the short day, or four for the full name, or five for the narrow name.
4 Tuesday
5 T
e 1..2 2 Local day of week. Same as E except adds a numeric value that will depend on the local starting day of the week, using one or two letters. For this example, Monday is the first day of the week.
3 Tues
4 Tuesday
5 T
c 1 2 Stand-Alone local day of week - Use one letter for the local numeric value (same as e), three for the short day, or four for the full name, or five for the narrow name.
3 Tues
4 Tuesday
5 T
period a 1 AM AM or PM
hour h 1..2 11 Hour [1-12].
H 1..2 13 Hour [0-23].
K 1..2 0 Hour [0-11].
k 1..2 24 Hour [1-24].
minute m 1..2 59 Minute. Use one or two for zero padding.
second s 1..2 12 Second. Use one or two for zero padding.
S 1..n 3457 Fractional Second - rounds to the count of letters. (example is for 12.34567)
A 1..n 69540000 Milliseconds in day. This field behaves exactly like a composite of all time-related fields, not including the zone fields. As such, it also reflects discontinuities of those fields on DST transition days. On a day of DST onset, it will jump forward. On a day of DST cessation, it will jump backward. This reflects the fact that is must be combined with the offset field to obtain a unique local time value.
zone z 1..3 PDT

fallbacks:
HPG-8:00
GMT-08:00
Timezone - with the specific non-location format. Where that is unavailable, falls back to localized GMT format. Use one to three letters for the short format or four for the full format. In the short format, metazone names are not used unless the commonlyUsed flag is on in the locale.

For more information about timezone formats, see Appendix J: Time Zone Display Names.

4 Pacific Daylight Time

fallbacks:
HPG-8:00
GMT-08:00
Z 1..3 -0800 Timezone - Use one to three letters for RFC 822 format, four letters for the localized GMT format.

For more information about timezone formats, see Appendix J: Time Zone Display Names.

4 HPG+8:00

fallbacks:
GMT-08:00
v 1 PT Timezone - with the generic non-location format. Where that is unavailable, uses special fallback rules given in Appendix J. Use one letter for short format, four for long format.

For more information about timezone formats, see Appendix J: Time Zone Display Names.

4 Pacific Time

fallbacks:
Pacific Time (Canada)
Pacific Time (Yellowknife)
United States (Los Angeles) Time
HPG-8:35
GMT-08:35
V 1 PST

fallbacks:
HPG-8:00
GMT-08:00
Timezone - with the same format as z, except that metazone timezone abbreviations are to be displayed if available, regardless of the value of commonlyUsed.

For more information about timezone formats, see Appendix J: Time Zone Display Names.

4 United States (Los Angeles) Time

fallbacks:
HPG-8:35
GMT-08:35
Timezone - with the generic location format. Where that is unavailable, falls back to the localized GMT format. (Fallback is only necessary with a GMT-style Timezone ID, like Etc/GMT-830.)

This is especially useful when presenting possible timezone choices for user selection, since the naming is more uniform than the v format.

For more information about timezone formats, see Appendix J: Time Zone Display Names.

This information is a subset of the Unicode Local Data Markup Language. Formatted for Day-O by Shaun Inman.