Loop through values of a SPSS variable inside of a Macro - macros

Question

How can I pass the values of a specific variable to a list-processing loop inside a macro?
Let's say, as an simplified example, I've got a variable foo which contains the values 1,4,12,33 and 51.
DATA LIST FREE / foo (F2) .
BEGIN DATA
1
4
12
33
51
END DATA.
And a macro that does some stuff with those values.
For testing reasons this Macro will just echo those values.
I'd like to find a way to run a routine that works like the following:
DEFINE !testmacro (list !CMDEND)
!DO !i !IN (!list)
ECHO !QUOTE(!i).
!DOEND.
!ENDDEFINE.
!testmacro list = 1 4 12 33 51. * <- = values from foo.

Answer 1

This is a situation where using the Python apis would be a good choice.

Answer 2

I made myself a little bit familiar with Python recently :-)
So this is what I worked out.
If the variable is a numeric:
BEGIN PROGRAM PYTHON.
import spss,spssdata
foolist = [element[0] for element in spssdata.Spssdata('foo').fetchall()]
foostring = " ".join(str(int(i)) for i in foolist)
spss.Submit("!testmacro list = %(foostring)s." %locals())
END PROGRAM.
If the variable is a string:
BEGIN PROGRAM PYTHON.
import spss,spssdata
foolist = [element[0].strip() for element in spssdata.Spssdata('bar').fetchall()]
foostring = " ".join(foolist)
spss.Submit("!testmacro list = %(foostring)s." %locals())
END PROGRAM.
Variants
Duplicates removed and list is orderd
BEGIN PROGRAM PYTHON.
import spss,spssdata
foolist = sorted(set([element[0] for element in spssdata.Spssdata('foo').fetchall()]))
foostring = " ".join(str(int(i)) for i in foolist)
spss.Submit("!testmacro list = %(foostring)s." %locals())
END PROGRAM.
Duplicates removed and items in order of first appearance in the dataset
Here, I use a function which I retrieved from Peter Bengtsson's Homepage (peterbe.com)
BEGIN PROGRAM PYTHON.
import spss,spssdata
def uniquify(seq, idfun=None):
# order preserving
if idfun is None:
def idfun(x): return x
seen = {}
result = []
for item in seq:
marker = idfun(item)
if marker in seen: continue
seen[marker] = 1
result.append(item)
return result
foolist = uniquify([element[0] for element in spssdata.Spssdata('foo').fetchall()])
foostring = " ".join(str(int(i)) for i in foolist)
spss.Submit("!testmacro list = %(foostring)s." %locals())
END PROGRAM.
Non-Python Solution
Not that I recommend it, but there is even a way to do this without Python.
I got the basic Idea from a SPSS programming book, which goes as follows:
Use the WRITE command to create a text file with the wanted command and variable values and include it with the insert command.
DATASET COPY foolistdata.
DATASET ACTIVATE foolistdata.
AGGREGATE OUTFILE=* MODE=ADDVARIABLES
/BREAK
/NumberOfCases=N.
* Variable which contains the command as string in the first case.
STRING macrocommand (A18).
IF ($casenum=1) macroCommand = "!testmacro list = ".
EXECUTE.
* variable which contains a period (.) in the last case,
* for the ending of the command string.
STRING commandEnd (A1).
IF ($casenum=NumberOfCases) commandEnd = ".".
* Write the 'table' with the command and variable values into a textfile.
WRITE OUTFILE="macrocommand.txt" /macrocommand bar commandEnd.
EXECUTE.
* Macrocall.
INSERT FILE ="macrocommand.txt".