SPSS® 12.0 Command Syntax Reference

60 Universals
The LIST output from these commands is shown in Figure 18.
Figure 18 Output illustrating WKDAY and MONTH formats
VAR1 VAR2 VAR3 VAR4 VAR5
SUNDAY 1 JANUARY JAN 1
MONDAY 2 FEBRUARY FEB 2
TUESDAY 3 MARCH MAR 3
WEDNESDAY 4 APRIL APR 4
THURSDAY 5 OCTOBER OCT 10
FRIDAY 6 NOVEMBER NOV 11
SATURDAY 7 DECEMBER DEC 12
Example
DATA LIST FIXED /VAR1 1-14 (DTIME) VAR2 18-42 (DATETIME).
BEGIN DATA
20 8:3 20-6-90 8:3
20:8:03:46 20/JUN/1990 8:03:46
20 08 03 46.75 20 June, 2001 08 03 46.75
END DATA.
LIST.
• DTIME and DATETIME read and write time intervals.
• The decimal point explicitly coded in the input data for fractional seconds.
• The DTIME format allows a − or + sign in the data value to indicate a time interval before
or after a point in time.
• Internally, values for a DTIME variable are stored as the number of seconds of the time
interval while those for a DATETIME variable are stored as the number of seconds from 0
hours, 0 minutes, and 0 seconds of Oct. 14, 1582.
The LIST output from these commands is shown in Figure 19.
Figure 19 Output illustrating DTIME and DATETIME formats
VAR1 VAR2
20 08:03:00 20-JUN-1990 08:03:00
20 08:03:46 20-JUN-1990 08:03:46
20 08:03:46 20-JUN-2001 08:03:46
Arithmetic Operations with Date and Time Variables
Most date and time variables are stored internally as the number of seconds from a particular
date or as a time interval and therefore can be used in arithmetic operations:
• A date is a floating-point number representing the number of seconds from midnight,
October 14, 1582. Dates, which represent a particular point in time, are stored as the
number of seconds to that date. For example, November 8, 1957, is stored as 1.2E+10.
• A date includes the time of day, which is the time interval past midnight. When time of
day is not given, it is taken as 00:00 and the date is an even multiple of 86,400 (the number
of seconds in a day).