SPSS Tutorials

BASICS REGRESSION T-TEST ANOVA CORRELATION

SPSS Scratch Variables

Definition

Scratch variables are temporary helper variables that don't show up in your data. A variable is a scratch variable if (and only if) its name starts with "#".

SPSS Scratch Variable - Introduction

SPSS Syntax Example

*1. Create data.

data list free / phone(a11).
begin data
020-2868825 020-8243613 075-6485421 010-9854183 0249-897201
010-0039658 0249-985638 023-5925133 020-0520029 075-3297331
end data.

*2. Determine position of "-" sign.

compute position = char.index(phone,'-').
exe.

*3. Extract area code by using substring.

string area (a4).
compute area = char.substr(phone,1,position - 1).
exe.

SPSS Scratch Variable - Example

SPSS Scratch Variable - Syntax Example

*1. Delete new variables prior to alternative approach.

delete variables position area.

*2. Determine position of "@" sign.

compute #position = char.index(phone,'-').

*3. Extract area code by using substring.

string area (a4).
compute area = char.substr(phone,1,#position - 1).
exe.

SPSS Scratch Variable - Special Features

SPSS Scratch Variable - Syntax Examples

*1. Create mini test dataset.

data list free/id.
begin data
1 2 3 4 5
end data.

*2. The calculation of #sum starts off from the previous value. Therefore, a cumulative sum is calculated like so.

compute #cumulative = sum(id,#cumulative).
compute cumulative = #cumulative.
exe.

*3. Delete 'cumulative' prior to next example.

delete variables cumulative.

*4. The first 'exe' triggers a data pass which deletes #cumulative. This causes the second 'compute' to fail.

compute #cumulative = sum(id,#cumulative).
exe.

compute cumulative = #cumulative.
exe.

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