Overview (DATE command)

DATE generates date identification variables. You can use these variables to label plots and other output, establish periodicity, and distinguish between historical, validation, and forecasting periods.

Options

You can specify the starting value and periodicity. You can also specify an increment for the lowest-order keyword specified.

Basic Specification

The basic specification on DATE is a single keyword.

  • For each keyword specified, DATE creates a numeric variable whose name is the keyword with an underscore as a suffix. Values for this variable are assigned to observations sequentially, beginning with the specified starting value. DATE also creates a string variable named DATE_, which combines the information from the numeric date variables and is used for labeling.
  • If no starting value is specified, either the default is used or the value is inferred from the starting value of another DATE keyword.
  • All variables created by DATE are automatically assigned variable labels that describe periodicity and associated formats. DATE produces a list of the names of the variables it creates and their variable labels.

Subcommand Order

  • Keywords can be specified in any order.

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 the topic Example 3 (DATE command) for more information.
  • 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 active dataset are deleted.
  • The DATE command invalidates any previous USE and PREDICT commands specified. The USE and PREDICT periods must be respecified after DATE.

Limitations

  • There is no limit on the number of keywords on the DATE command. However, keywords that describe long time periods (YEAR, QUARTER, MONTH) cannot be used on the same command with keywords that describe short time periods (WEEK, DAY, HOUR, MINUTE, SECOND).
  • User-defined variable names must not conflict with DATE variable names.