* Expressions:: Numeric and string expression syntax.
* Data Input and Output:: Reading data from user files.
* Expressions:: Numeric and string expression syntax.
* Data Input and Output:: Reading data from user files.
* Variable Attributes:: Adjusting and examining variables.
* Data Manipulation:: Simple operations on data.
* Data Selection:: Select certain cases for analysis.
* Variable Attributes:: Adjusting and examining variables.
* Data Manipulation:: Simple operations on data.
* Data Selection:: Select certain cases for analysis.