SPSS notes

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Page 70-71 of PASW/SPSS 18 User Manual

[edit] Variable Names

The following rules apply to variable names:

• Each variable name must be unique; duplication is not allowed.
• Variable names can be up to 64 bytes long, and the first character must be a letter or one ofthe characters @, #, or $. Subsequent characters can be any combination of letters, numbers, nonpunctuation characters, and a period (.). In code page mode, sixty-four bytes typicallymeans 64 characters in single-byte languages (for example, English, French, German, Spanish, Italian, Hebrew, Russian, Greek, Arabic, and Thai) and 32 characters in double-byte languages (for example, Japanese, Chinese, and Korean). Many string characters that only take one byte in code page mode take two or more bytes in Unicode mode. For example, é is one byte in code page format but is two bytes in Unicode format; so résumé is six bytes in a code page file and eight bytes in Unicode mode.

Note: Letters include any nonpunctuation characters used in writing ordinary words in the languages supported in the platform’s character set.

• Variable names cannot contain spaces.
• A # character in the first position of a variable name defines a scratch variable. You can only create scratch variables with command syntax. You cannot specify a # as the first character of a variable in dialog boxes that create new variables.
• A $ sign in the first position indicates that the variable is a system variable. The $ sign is not allowed as the initial character of a user-defined variable.
• The period, the underscore, and the characters $, #, and @ can be used within variable names. For example, A._$@#1 is a valid variable name.
• Variable names ending with a period should be avoided, since the period may be interpreted as a command terminator. You can only create variables that end with a period in command syntax. You cannot create variables that end with a period in dialog boxes that create new variables.
• Variable names ending in underscores should be avoided, since such names may conflict with names of variables automatically created by commands and procedures.
• Reserved keywords cannot be used as variable names. Reserved keywords are ALL, AND, BY, EQ, GE, GT, LE, LT, NE, NOT, OR, TO, and WITH.
• Variable names can be defined with any mixture of uppercase and lowercase characters, and case is preserved for display purposes.
• When long variable names need to wrap onto multiple lines in output, lines are broken at underscores, periods, and points where content changes from lower case to upper case.

[edit] Variable Labels

You can assign descriptive variable labels up to 256 characters (128 characters in double-byte languages). Variable labels can contain spaces and reserved characters that are not allowed in variable names.