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Date and Time Patterns

Date and time formats are specified by date and time pattern strings.

Within date and time pattern strings, unquoted letters from A to Z and from a to z are interpreted as patterns representing the components of a date or time string. Text surrounded by single quotes (') is interpreted as literal text. To include the text character for a single quote as literal text, use a double quote ("). All other characters are not interpreted; they are copied into the output string during formatting or matched against the input string during parsing.

The following pattern letters are defined (all other characters from A to Z and from a to z are reserved).

Letter Date or Time Component Presentation Examples
G Era designator Text AD
y Year Year 1996; 96
M Month in year Month July; Jul; 07
w Week in year Number 27
W Week in month Number 2
D Day in year Number 189
d Day in month Number 10
F Day of week in month Number 2
E Day in week Text Tuesday; Tue
a AM/PM marker Text PM
H Hour in day (0-23) Number 0
k Hour in day (1-24) Number 24
K Hour in am/pm (0-11) Number 0
h Hour in am/pm (1-12) Number 12
m Minute in hour Number 30
s Second in minute Number 55
S Millisecond Number 978
z Time zone General time zone Pacific Standard Time; PST; GMT-08:00
Z Time zone RFC 822 time zone -0800
Pattern letters are usually repeated as their number determines the exact presentation:
  • Text: If the number of pattern letters is four or more, the full form is used; otherwise a short or abbreviated form is used if available.
  • Number: The number of pattern letters is the minimum number of digits, and shorter numbers are zero-padded to this amount.
  • Year: If the number of pattern letters is two, the year is truncated to two digits; otherwise it is interpreted as a number.
  • Month: If the number of pattern letters is 3 or more the month is interpreted as text; otherwise it is interpreted as a number.
  • General time zone: Time zones are interpreted as text if they have names. For time zones representing a GMT offset value, the syntax GMT Sign Hours:mm is used, where Sign is + or -; Hours is H or HH and must be between 0 and 23; and mm must be between 00 and 59. The format is locale-independent and digits must be taken from the Basic Latin block of the Unicode standard.
  • RFC 822 time zone: The four-digit time zone format of Sign Hours:mm is used, where Sign is + or -; and Hours is HH and must be between 00 and 23. Other definitions are as for general time zone.

Examples

The following examples show how date and time patterns are interpreted in the U.S. locale. The date and time represented in these examples is 2001-07-04 12:08:56 local time in the U.S. Pacific Time time zone.

Date and Time Pattern Result
"yyyy.MM.dd G 'at' HH:mm:ss z" 2001.07.04 AD at 12:08:56 PDT
"EEE MMM d ''yy" Wed Jul 4 '01
"h:mm a" 12:08 PM
"hh 'o''clock' a zzzz" 12 o'clock PM Pacific Daylight Time
"K:mm a z" 0:08 PM PDT
"yyyyy.MMMMM.dd GGG hh:mm aaa" 02001.July.04 AD 12:08 PM
"EEE d MMM yyyy HH:mm:ss Z" Wed 4 Jul 2001 12:08:56 -0700
"yyMMddHHmmssZ" 010704120856-0700

This example shows how the entire date/time value can be formatted in a single call: 

$DateTime (simple-variable-value format-string)

Where: format-string: a date and time pattern

Note: $DateTime does not include the parameter lang-code for presenting date and time patterns in a language other than the designated default language.
Example: 
$DateTime (${CT}, "EEE dd MMM yyyy HH:mm:ss Z")
 

Formal Grammar

The formal grammar presented below defines variable values in Extended BNF (Bakus-Naur Form):
  • ' ' - literal value
  • ( ) - group of values
  • | - choice
  • ? - multiplicity 0 or 1
  • * - multiplicity 0 or more
  • + - multiplicity 1 or more
  • #xnnnn - 16 bit hexadecimal value
Variable Value Comments
variable-value ::== ( literal-string | variable-evaluation | function)*
literal-string ::== ( unicode-character | character-escape )+ /* allows $VAR or $FUNC(...) or ${VAR} */
variable-evaluation :== '$' ( variable-name | '{' variable-name '}')
variable-name :== identifier
function :== function-name '(' parameters ')
function-name :== ( '$Bates' | '$RomanNum' | '$RomanLowerNum' )
parameters :== variable-evaluation ( ',' digit+ )? variable-evaluation must resolve to a numeric value
identifier :== letter ( letter | digit )*
character-escape ::== '\' ( '$' | '\' | '(' | ')' )
letter ::== [ 'a' - 'z' ] | [ 'A' - 'Z' ] | '_'
digit :== ['0'-'9']
unicode-character ::== [ #x0020 - #x0023 ] |

[ #x0025 - #x0026 ] |

[ #x0029 - #x005B ] |

[ #x005D - #x007F ] |

[ #x00A0 - #xD7FF ] |

[#xE000 - #xFFFD ]