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4 Processing Data

Developer’s Guide

Proposed outline:

* Introduction
* Basic concepts
** Data sets
** Variables
** Dictionaries
** Coding conventions
** Pools
* Syntax parsing
* Data processing
** Reading data
*** Casereaders generalities
*** Casereaders from data files
*** Casereaders from the active dataset
*** Other casereaders
** Writing data
*** Casewriters generally
*** Casewriters to data files
*** Modifying the active dataset
**** Modifying cases obtained from active dataset casereaders has no real effect
**** Transformations; procedures that transform
** Transforming data
*** Sorting and merging
*** Filtering
*** Grouping
**** Ordering and interaction of filtering and grouping
*** Multiple passes over data
*** Counting cases and case weights
** Best practices
*** Multiple passes with filters versus single pass with loops
*** Sequential versus random access
*** Managing memory
*** Passing cases around
*** Renaming casereaders
*** Avoiding excessive buffering
*** Propagating errors
*** Avoid static/global data
*** Don't worry about null filters, groups, etc.
*** Be aware of reference counting semantics for cases