User Guide

156
Chapter 7
Select Variables to Merge into Single Date/Time Variable
Figure 7-19
Create date/
time variable from variable set, step 1
E Select the variables that represent the different parts of the date/time.
 Some combinations of selections are not allowed. For instance, creating a
date/t
ime variable from Year and Day of Month is invalid because once Year is
chosen, a full date is required.
 You cannot use an existing date/time variable as one of the parts of the final
date/time variable you’re creating. Variables that make up the parts of the
new dat
e/time variable must be integers. The exception is the allowed use of
an existing date/time variable as the Seconds part of the new variable. Since
fractional seconds are allowed, the variable used for Seconds is not required
to be a
ninteger.
 Val u
es, for any part of the new variable, that are not within the allowed range,
result in a value of system-missing for the new variable. For instance, if you
inadvertently use a variable representing day of month for Month. Since the valid
range
for months in SPSS is 1–13, any cases with day of month values in the
range 14–31 will be assigned the system-missing value for the new variable.