SPSS System Variables

System variables track the current state of the interpretter.

The dollar sign ($) is a disallowed leading character for user-defined variables because this is reserved for system variables.

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CaseNum

$CASENUM holds the current case's row number.

To create an 8-digit unique identifier number, try:

compute UniqueID = 10000000 + $casenum.

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Date

$DATE holds the current date. Use $TIME instead of this.

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Time

$TIME holds the current date and time as the number of seconds from October 14, 1582, to the execution time of a command accessing it.

This can be used to construct a timestamp.

data list free / a.
begin data.
1
end data.
dataset name TIMESTAMP.
execute.

string timestamp (A20).
compute #time = $time.

compute timestamp=concat(
  char.substr(string(xdate.year(#time),N4),3,2),
  string(xdate.month(#time),N2),
  string(xdate.mday(#time),N2),
  "_",
  string(xdate.hour(#time),N2),
  string(xdate.minute(#time),N2),
).
execute.

do if $casenum=1.
  write outfile 'timestamp.sps' /1 "define !timestamp() " timestamp " !enddefine.".
end if.
dataset close TIMESTAMP.
execute.

insert file='timestamp.sps'.
execute.
erase file='timestamp.sps'.

!timestamp() can now be used to reference the current date and time.

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