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In SPSS the keyword "to" as two different meanings that depend on the context in which the word is used.
If existing variables are being manipulated, "to" means positionally consecutive. "Positionally consecutive" means that all of the variables in between the two listed in the command will have the operation performed on them, regardless of the numeric suffixes of the variables. For example, if you have the variables a1 a2 b1 a3 in that order in your data set and issue the recode command using "to", recode a1 to a3, all four variables will be recoded.
The keyword "to" can also be used to indicate numeric consecutiveness. "Numerically consecutive" means that variables with the same prefix and numeric suffixes will be considered, regardless of their position in the data set. In SPSS, if the command will create new variables, then the keyword "to" will act in a numerically consecutive manner. For example, if you issue the do repeat command to create a series of new variables, SPSS will create the new variables with whatever prefix you specify (e.g., newvar) and consecutive numeric suffixes (e.g., 1, 2, 3 etc.).
We will use the following hypothetical data set to illustrate how some of the commands use the keyword "to".
data list list / num1 num2 num5 pos1 pos2 snorf pos3 x z. begin data 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 2 1 3 1 1 1 1 1 1 2 1 4 1 end data. execute. save outfile 'c:\to.sav'.
recode pos1 to pos3 (1 = 0).
list.
NUM1 NUM2 NUM5 POS1 POS2 SNORF POS3 X Z
1.00 1.00 1.00 .00 .00 .00 .00 1.00 1.00
1.00 1.00 1.00 .00 .00 .00 .00 2.00 1.00
1.00 1.00 1.00 .00 .00 2.00 .00 3.00 1.00
1.00 1.00 1.00 .00 .00 2.00 .00 4.00 1.00
Number of cases read: 4 Number of cases listed: 4
missing values pos1 to pos3 (8,9).
display dictionary.
List of variables on the working file
Name Position
NUM1 1
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
NUM2 2
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
NUM5 3
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
POS1 4
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
Missing Values: 8.00, 9.00
POS2 5
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
Missing Values: 8.00, 9.00
SNORF 6
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
Missing Values: 8.00, 9.00
POS3 7
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
Missing Values: 8.00, 9.00
X 8
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
Z 9
Measurement Level: Scale
Column Width: 8 Alignment: Right
Print Format: F8.2
Write Format: F8.2
As you can see, all of the variables between pos1 and pos3, including snorf, were recoded and had missing values assigned to them.
If you need to reorder the variables in your data set to make them positionally consecutive, you can use either the save or the xsave command with the /keep statement. The variables will be saved in the order in which they are listed on the /keep statement. Note that any variables not listed on the /keep statement will be dropped. To avoid potential problems, you can list the variables that you want first in the data set in the order that you need, and then use the SPSS keyword "all". This will include all of the variables not already listed, in the order in which they are in the current data set. For example,
save outfile 'c:\test1.sav' /keep pos1 to pos3 all /map. OUTPUT FILE MAP Result Input1 ------ ------ POS1 POS1 POS2 POS2 SNORF SNORF POS3 POS3 NUM1 NUM1 NUM2 NUM2 NUM5 NUM5 X X Z Zget file 'c:\test1.sav'. list. POS1 POS2 SNORF POS3 NUM1 NUM2 NUM5 X Z .00 .00 .00 .00 1.00 1.00 1.00 1.00 1.00 .00 .00 .00 .00 1.00 1.00 1.00 2.00 1.00 .00 .00 2.00 .00 1.00 1.00 1.00 3.00 1.00 .00 .00 2.00 .00 1.00 1.00 1.00 4.00 1.00 Number of cases read: 4 Number of cases listed: 4Also note that the keyword "to" is used in the /keep subcommand. Again, because it refers to variables that already exist in the data set, "to" acts positionally.
The do repeat and vector commands create new variables and act in a numerically consecutive manner.
do repeat v = nu1 to nu5. compute v = 0. end repeat. execute. list.The variables are listed in the following order: LINE 1: POS1 POS2 SNORF POS3 NUM1 NUM2 NUM5 LINE 2: X Z NU1 NU2 NU3 NU4 NU5 POS1: .00 .00 .00 .00 1.00 1.00 1.00 X: 1.00 1.00 .00 .00 .00 .00 .00 POS1: .00 .00 .00 .00 1.00 1.00 1.00 X: 2.00 1.00 .00 .00 .00 .00 .00 POS1: .00 .00 2.00 .00 1.00 1.00 1.00 X: 3.00 1.00 .00 .00 .00 .00 .00 POS1: .00 .00 2.00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 Number of cases read: 4 Number of cases listed: 4 vector Anum = num1 to num5. loop x = 1 to 3. compute nm = Anum(x). end loop. execute. list. The variables are listed in the following order: LINE 1: POS1 POS2 SNORF POS3 NUM1 NUM2 NUM5 LINE 2: X Z NU1 NU2 NU3 NU4 NU5 LINE 3: NM POS1: .00 .00 .00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 POS1: .00 .00 .00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 POS1: .00 .00 2.00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 POS1: .00 .00 2.00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 Number of cases read: 4 Number of cases listed: 4
There are some commands in SPSS that act in both a positionally and a numerically consecutive manner. These commands make modifications to existing variables and create new variables with the modified values. Hence, the keyword "to" acts positionally in these commands when variables that already exist in the data set are being referenced. When new variables are being created, "to" acts numerically.
Example 1
autorecode pos1 to pos3 /into ppos1 to ppos4. list. The variables are listed in the following order: LINE 1: POS1 POS2 SNORF POS3 NUM1 NUM2 NUM5 LINE 2: X Z NU1 NU2 NU3 NU4 NU5 LINE 3: NM PPOS1 PPOS2 PPOS3 PPOS4 POS1: .00 .00 .00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 1 1 1 1 POS1: .00 .00 .00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 1 1 1 1 POS1: .00 .00 2.00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 1 1 2 1 POS1: .00 .00 2.00 .00 1.00 1.00 1.00 X: 4.00 1.00 .00 .00 .00 .00 .00 NM: 1.00 1 1 2 1 Number of cases read: 4 Number of cases listed: 4As you can see, all of the variables between pos1 and pos3 (including snorf), were autorecoded. We needed to specify four names because there were four variables between pos1 and pos3 (including pos1 and pos3).
Example 2
aggregate outfile 'c:\test.sav'
/break snorf
/maxpos1 to maxpos2 = max(pos1 to pos2).
get file 'c:\test.sav'.
list.
SNORF MAXPOS1 MAXPOS2
.00 .00 .00
2.00 .00 .00
Number of cases read: 2 Number of cases listed: 2
In the example above, maxpos1 and maxpos2 are variables that are created by the aggregate command; hence, the keyword "to" is numerically consecutive. However, the max function is operating on variables that already exist in the data set; hence, they must by positionally consecutive.
Example 3
get file 'c:\to.sav'.
rename variables (pos1 to pos3 = p1 to p4).
list.
NUM1 NUM2 NUM5 P1 P2 P3 P4 X Z
1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
1.00 1.00 1.00 1.00 1.00 1.00 1.00 2.00 1.00
1.00 1.00 1.00 1.00 1.00 2.00 1.00 3.00 1.00
1.00 1.00 1.00 1.00 1.00 2.00 1.00 4.00 1.00
Number of cases read: 4 Number of cases listed: 4
In this example, we see again that the keyword "to" is acting positionally: we needed to give four names after the equals sign (p1, p2, p3 and p4) because there are four variable between pos1 and pos3 (including these variables).
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