2 @chapter Processing Data
19 *** Casereaders generalities
20 *** Casereaders from data files
21 *** Casereaders from the active file
24 *** Casewriters generally
25 *** Casewriters to data files
26 *** Modifying the active file
27 **** Modifying cases obtained from active file casereaders has no real effect
28 **** Transformations; procedures that transform
30 *** Sorting and merging
33 **** Ordering and interaction of filtering and grouping
34 *** Multiple passes over data
35 *** Counting cases and case weights
37 *** Multiple passes with filters versus single pass with loops
38 *** Sequential versus random access
40 *** Passing cases around
41 *** Renaming casereaders
42 *** Avoiding excessive buffering
43 *** Propagating errors
44 *** Avoid static/global data
45 *** Don't worry about null filters, groups, etc.
46 *** Be aware of reference counting semantics for cases