1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
* (Q) Find all combinations of 1, 2, ..., n items out of m items.

* (A) by rlevesque@videotron.ca 2001/08/30;
	SPSS Dedicated web site http://pages.infinit.net/rlevesqu/index.htm.

* Note: This is a complex syntax but it is very easy to use. See the example at the end.
*	3 macros are defined by the syntax,
	the first of these macros (combina) writes a syntax file 
	which subsequently writes a text file. The text file is read into the data editor and 
	used to write all combinations.


SET MPRINT=no.

*/////////////////////////////.
DEFINE !combine (n=!TOKENS(1) 
	/items=!CMDEND).

/* Find all combinations of 1,2, ... n items out of m items*/
/* August 30,2001 rlevesque@videotron.ca */

* Count number of variables.
!LET !nb=!NULL
!DO !cnt !IN (!items)
!LET !nb=!CONCAT(!nb,!BLANK(1))
!DOEND
!LET !m=!LENGTH(!nb)

!DO !thisn=1 !TO !n
NEW FILE.
INPUT PROGRAM.
LOOP i=1 TO !thisn.
END CASE.
END LOOP.
END FILE.
END INPUT PROGRAM.
LIST.

!LET !list=!NULL
!DO !cnt=1 !TO !thisn
	!LET !list=!CONCAT(!list," ","j",!cnt)
!DOEND

COMPUTE n=!thisn.

* Calculate variable names for LOOP of the next WRITE command *.
STRING cntname cntbeg(A8).

COMPUTE cntname=CONCAT('j',LTRIM(STRING(i,F8.0))).

* Calculate first parameter for the LOOP of the next WRITE command *.
DO IF i=1.
COMPUTE cntbeg="1".
ELSE.
COMPUTE cntbeg=CONCAT('j',LTRIM(STRING(i-1,F8.0))," + 1").
END IF.

* Calculate second parameter for the LOOP of the next WRITE command *.
COMPUTE k=!m - !thisn + i.
FORMATS i k n(F8.0).

STRING quote(A1) strlist(A255).
COMPUTE quote='"'.
COMPUTE strlist=!QUOTE(!list).

* Write the syntax file which will store all the combinations in the list.txt file*.
WRITE OUTFILE "c:\\temp\\macro.sps" 
	/"LOOP "cntname"="cntbeg" TO "k".".
DO IF i=!thisn.
+	WRITE OUTFILE "c:\\temp\\macro.sps" 
	/"WRITE OUTFILE "quote"c:\\temp\\list.txt"quote "/" strlist "." .
+	LOOP cnt=1 TO !thisn.
+		WRITE OUTFILE "c:\\temp\\macro.sps" /"END LOOP.".
+	END LOOP.
+	WRITE OUTFILE "c:\\temp\\macro.sps" /"EXECUTE.". 
END IF.
EXECUTE.
INCLUDE FILE="c:\\temp\\macro.sps".

/* Convert data from list.txt to the corresponding sav file */.
DATA LIST FILE='c:\\temp\\list.txt' LIST /!list.
SAVE OUTFILE=!QUOTE(!CONCAT('c:\\temp\\list',!thisn,'.sav')).
!DOEND

/* Combine all the sav files */.
GET FILE='c:\\temp\\list1.sav'.
!DO !nb=2 !TO !n.
ADD FILES FILE=* 
	/FILE=!QUOTE(!CONCAT('c:\\temp\\list',!nb,'.sav.')).
!DOEND

/* Eliminate duplicates  */.
SORT CASES BY ALL.
MATCH FILES FILE=* /BY=ALL /FIRST=first.
SELECT IF first.
SAVE OUTFILE='c:\\temp\\all combinations.sav'.

/* Find name of last variables */
!DO !var !IN (!items)
!LET !lastone=!var
!DOEND

VECTOR vnames(!m A8).
!LET !cnt=!BLANK(1)

/* Create variables containing the names of the items variables */
!DO !var !IN (!items)
COMPUTE vnames(!LEN(!cnt))=!QUOTE(!var).
!LET !cnt=!CONCAT(!cnt,!BLANK(1))
!DOEND

/* Construct the string containing the list of combinations */.
STRING items(A255).
VECTOR j=j1 TO !CONCAT('j',!n) /ind=vnames1 TO  !CONCAT('vnames',!m).
COMPUTE nvar=NVALID(j1 TO !CONCAT('j',!n)).
LOOP cnt=1 TO nvar.
COMPUTE items=CONCAT(RTRIM(items)," ",vnames(j(cnt))).
END LOOP.

EXECUTE.

!ENDDEFINE.
*////////////////////////////.


*************************.
* EXAMPLES OF USE.
*************************.

SET MPRINT=yes.
!combine n=5 items=educ jobcat jobtime prevexp minority.

* Example 2.
!combine n=3 items=a b c d e f g.