SPSS® 12.0 Command Syntax Reference

Date and Time
SPSS reads and writes date and time in many different formats but stores them as floatingpoint
numbers. You can perform arithmetic operations on them, use them in statistical
procedures, and display or print them in a format of your choice. This section discusses the
input and output formats for date and time, arithmetic operations using date and time
variables, and date and time functions.
Date and Time Formats
Date and time formats are both input and output formats. They can be used on DATA LIST and
other variable definition commands to read in values representing dates or times or date-time
combinations. Like numeric formats, each input format generates a default output format,
automatically expanded (if necessary) to accommodate display width. In addition, you can
assign or modify output formats using FORMATS, WRITE FORMATS, and PRINT FORMATS
commands. The output formats are effective only with LIST, REPORT, and TABLES procedures
and the PRINT and WRITE transformation commands. Other procedures use the F format and
display the values as numbers.
• All date and time formats have a minimum input width, and some have a different
minimum output. Wherever the input minimum width is less than the output minimum,
SPSS expands the width automatically when displaying or printing values. However,
when you specify output formats, you must allow enough space for displaying the date
and time in the format you choose.
• Input data shorter than the specified width are correctly evaluated as long as all the
necessary elements are present. For example, with the TIME format, 1:2, 01 2, and 01:02
are all correctly evaluated even though the minimum width is 5. However, if only one
element (hours or minutes) is present, you must use a time function to aggregate or
convert the data (see “Date and Time Functions” on p. 62).
• If a date or time value cannot be completely displayed in the specified width, values are
truncated in the output. For example, an input time value of 1:20:59 (1 hour, 20 minutes,
59 seconds) displayed with a width of 5 will generate an output value of 01:20, not
01:21. The truncation of output does not affect the numeric value stored in the working
file.
Table 7 shows all available date and time formats, where w indicates the total number of
columns and d (if present), the number of decimal places for fractional seconds. The
example shows the output format with the minimum width and default decimal positions (if
applicable). The format allowed in the input data is much less restrictive (see “Input Data
Specification” on p. 57).
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