Append Mode (Python)

This mode is used to append new cases to the active dataset. It cannot be used to add new variables or read case data from the active dataset. A dataset must contain at least one variable in order to append cases to it, but it need not contain any cases. Append mode is specified with spss.Cursor(accessType='a').

  • The CommitCase method must be called for each case that is added.
  • The EndChanges method must be called before the cursor is closed.
  • Changes to the active dataset do not take effect until the cursor is closed.
  • A numeric variable whose value is not specified (for a new case) is set to the system-missing value.
  • A string variable whose value is not specified (for a new case) will have a blank value. The value will be valid unless you explicitly define the blank value to be missing for that variable.
  • The Cursor methods SetValueChar and SetValueNumeric are used to set variable values for new cases.

Example

DATA LIST FREE /var1 (F) var2 (A2)  var3 (F).
BEGIN DATA
11 ab 13
21 cd 23
31 ef 33
END DATA.
BEGIN PROGRAM.
import spss
cur=spss.Cursor(accessType='a')
ncases=cur.GetCaseCount()
newcases=2
for i in range(newcases):
   cur.SetValueNumeric('var1',1+10*(ncases+i+1))
   cur.SetValueNumeric('var3',3+10*(ncases+i+1))
   cur.CommitCase()
cur.EndChanges()
cur.close()
END PROGRAM.
  • An instance of the Cursor class in append mode is created and assigned to the variable cur.
  • The SetValueNumeric method is used to set the case values of var1 and var3 for two new cases. No value is specified for var2. The CommitCase method is called to commit the values for each case.
  • The EndChanges method is called to commit the new cases to the cursor.