Automatic inference of measeurement level works.

[pspp] / doc / data-selection.texi

diff --git a/doc/data-selection.texi b/doc/data-selection.texi
index 17c039c88d16d3b3f95111c95212f8dc9eb2f2a1..b92d1826efe79d804d582aeae8384197e2064a13 100644 (file)
--- a/doc/data-selection.texi
+++ b/doc/data-selection.texi
@@ -156,11 +156,38 @@ deleted from the data stream.
 Place @cmd{SELECT IF} as early in the command file as
 possible.  Cases that are deleted early can be processed more
 efficiently in time and space.
+Once cases have been deleted from the active dataset using @cmd{SELECT IF} they
+cannot be re-instated.
+If you want to be able to re-instate cases, then use @cmd{FILTER} (@pxref{FILTER})
+instead.
 
 When @cmd{SELECT IF} is specified following @cmd{TEMPORARY}
 (@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
 (@pxref{LAG}).
 
+@subsection Example Select-If
+
+A shop steward is interested in the salaries of younger personnel in a firm.
+The file @file{personnel.sav} provides the salaries of all the workers and their
+dates of birth.  The syntax in @ref{select-if:ex} shows how @cmd{SELECT IF} can
+be used to limit analysis only to those persons born after December 31, 1999.
+
+@float Example, select-if:ex
+@psppsyntax {select-if.sps}
+@caption {Using @cmd{SELECT IF} to select persons born on or after a certain date.}
+@end float
+
+From @ref{select-if:res} one can see that there are 56 persons listed in the dataset,
+and 17 of them were born after December 31, 1999.
+
+@float Result, select-if:res
+@psppoutput {select-if}
+@caption {Salary descriptives before and after the @cmd{SELECT IF} transformation.}
+@end float
+
+Note that the @file{personnel.sav} file from which the data were read is unaffected.
+The transformation affects only the active file.
+
 @node SPLIT FILE
 @section SPLIT FILE
 @vindex SPLIT FILE
@@ -181,12 +208,15 @@ An independent analysis is carried out for each group of cases, and the
 variable values for the group are printed along with the analysis.
 
 When a list of variable names is specified, one of the keywords
-@subcmd{LAYERED} or @subcmd{SEPARATE} may also be specified.  If provided, either
-keyword are ignored.
+@subcmd{LAYERED} or @subcmd{SEPARATE} may also be specified.  With
+@subcmd{LAYERED}, which is the default, the separate analyses for each
+group are presented together in a single table.  With
+@subcmd{SEPARATE}, each analysis is presented in a separate table.
+Not all procedures honor the distinction.
 
 Groups are formed only by @emph{adjacent} cases.  To create a split
 using a variable where like values are not adjacent in the working file,
-you should first sort the data by that variable (@pxref{SORT CASES}).
+first sort the data by that variable (@pxref{SORT CASES}).
 
 Specify @subcmd{OFF} to disable @cmd{SPLIT FILE} and resume analysis of the
 entire active dataset as a single group of data.
@@ -227,6 +257,17 @@ split.
 
 Unless @cmd{TEMPORARY} was used, after a split has been defined for
 a dataset it remains active until explicitly disabled.
+In the graphical user interface, the active split variable (if any) is
+displayed in the status bar (@pxref{split-status-bar:scr}.
+If a dataset is saved to a system file (@pxref{SAVE}) whilst a split
+is active, the split stastus is stored in the file and will be
+automatically loaded when that file is loaded.
+
+@float Screenshot, split-status-bar:scr
+@psppimage {split-status-bar}
+@caption {The status bar indicating that the data set is split using the @exvar{treatment} variable}
+@end float
+
 
 @node TEMPORARY
 @section TEMPORARY