SPSS® 12.0 Command Syntax Reference

DATE 433
• The starting value is specified first, followed by the periodicity, if any.
• You cannot specify a periodicity without first specifying a starting value.
• Starting values for HOUR, MINUTE, and SECOND can range from 0 to the periodicity
minus 1 (for example, 0 to 59). For all other keywords, the range is 1 to the periodicity.
• If both MONTH and QUARTER are specified, DATE can infer the starting value of one from
the other (see “Example 5” on p. 437).
• Specifying conflicting starting values for MONTH and QUARTER, such as Q 1 M 4, results
in an error.
• For keyword YEAR, the starting value can be specified as the last two digits (93) instead
of the whole year (1993) when the series and any forecasting are all within the same
century. The same format (2 digits or 4 digits) must be used in all other commands that
use year values.
• If you specify keywords that describe short time periods and skip over a level of measurement
(for example, if you specify HOUR and SECOND but not MINUTE), you must specify
the starting value and periodicity of the keyword after the skipped keywords. Otherwise,
inappropriate periodicities will be generated (see “Example 7” on p. 438).
BY Keyword
• Keyword BY and a positive integer can be specified after the lowest-order keyword on the
command to indicate an increment value. This value indicates how much to increment
values of the lowest-order date variable as they are assigned to observations (see
“Example 4” on p. 436).
• The increment value must divide evenly into the periodicity of the lowest-order DATE
variable specified.
Operations
• DATE creates a numeric variable for every keyword specified, plus a string variable
DATE_, which combines information from all the specified keywords.
• DATE automatically creates variable labels for each keyword specified indicating the variable
name and its periodicity. For the DATE_ variable, the label indicates the variable
name and format.
• If the highest-order DATE variable specified has a periodicity, the CYCLE_ variable will
automatically be created. CYCLE_ cannot have a periodicity (see “Example 3” on p. 435).
• Default periodicities are not used for the highest-order keyword specified. The exception
is QUARTER, which will always have a default periodicity.
• The periodicity of the lowest-order variable is the default periodicity used by the procedures
when periodicity is not defined either within the procedure or by the TSET command.
• The keyword name with an underscore is always used as the new variable name, even if
keyword abbreviations are used in the specifications.
• Each time the DATE command is used, any DATE variables already in the working data file
are deleted.