Formatting Date and Datetime Values

Working with Time Series Data

Formatting Date and Datetime Values

The SAS System provides formats to convert the internal representation of date and datetime values used by SAS to ordinary notations for dates and times. Several different formats are available for displaying dates and datetime values in most of the commonly used notations.

A SAS format is aan instruction that converts the internal numerical value of a SAS variable to a character string that can be printed or displayed. Date formats convert SAS date values to a readable form; datetime formats convert SAS datetime values to a readable form.

In the preceding example, the variable DATE was set to the SAS date value for the first day of the month for each observation. If the data set USCPI were printed or otherwise displayed, the values shown for DATE would be the number of days since 1 January 1960. (See the "DATE with no format" column in Figure 2.2.) To display date values appropriately, use the FORMAT statement.

The following example processes the data set USCPI to make several copies of the variable DATE and uses a FORMAT statement to give different formats to these copies. The format cases shown are the MONYY7. format (for the DATE variable), the DATE9. format (for the DATE1 variable), and no format (for the DATE0 variable). The PROC PRINT output in Figure 2.2 shows the effect of the different formats on how the date values are printed.

   data fmttest;
      set uscpi;
      date0 = date;
      date1 = date;
      label date  = "DATE with MONYY7. format"
            date1 = "DATE with DATE9. format"
            date0 = "DATE with no format";
      format date monyy7. date1 date9.;
   run;
   
   proc print data=fmttest label;
   run;

Obs	DATE with MONYY. format	cpi	DATE with no format	DATE with DATE. format
1	JUN1990	129.9	11109	01JUN1990
2	JUL1990	130.4	11139	01JUL1990
3	AUG1990	131.6	11170	01AUG1990
4	SEP1990	132.7	11201	01SEP1990
5	OCT1990	133.5	11231	01OCT1990
6	NOV1990	133.8	11262	01NOV1990
7	DEC1990	133.8	11292	01DEC1990
8	JAN1991	134.6	11323	01JAN1991
9	FEB1991	134.8	11354	01FEB1991
10	MAR1991	135.0	11382	01MAR1991

Figure 2.2: SAS Date Values Printed with Different Formats

The appropriate format to use for SAS date or datetime valued ID variables depends on the sampling frequency or periodicity of the time series. Table 2.2 shows recommended formats for common data sampling frequencies and shows how the date '17OCT1991'D or the datetime value '17OCT1991:14:45:32'DT is displayed by these formats.

Table 2.2: Formats for Different Sampling Frequencies

ID values	Periodicity	FORMAT	Example
SAS Date	Annual	YEAR4.	1991
	Quarterly	YYQC6.	1991:4
	Monthly	MONYY7.	OCT1991
	Weekly	WEEKDATX23.	Thursday, 17 Oct 1991
		DATE9.	17OCT1991
	Daily	DATE9.	17OCT1991
SAS Datetime	Hourly	DATETIME10.	17OCT91:14
	Minutes	DATETIME13.	17OCT91:14:45
	Seconds	DATETIME16.	17OCT91:14:45:32

See Chapter 3 for more information on the date and datetime formats available.

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