@item FIRST(var_name)
First non-missing value in break group. The aggregation variable
receives the complete dictionary information from the source variable.
+The sort performed by AGGREGATE (and by SORT CASES) is stable, so that
+the first case with particular values for the break variables before
+sorting will also be the first case in that break group after sorting.
@item FOUT(var_name, low, high)
Fraction of values strictly outside the specified range of constants.
@item LAST(var_name)
Last non-missing value in break group. The aggregation variable
receives the complete dictionary information from the source variable.
+The sort performed by AGGREGATE (and by SORT CASES) is stable, so that
+the last case with particular values for the break variables before
+sorting will also be the last case in that break group after sorting.
@item MAX(var_name)
Maximum value. The aggregation variable receives the complete
variables are selected for transposition.
The variables specified by NEWNAMES, which must be a string variable, is
-used to give names to the variables created by @cmd{FLIP}. If
+used to give names to the variables created by @cmd{FLIP}. Only the
+first 8 characters of the variable are used. If
NEWNAMES is not
specified then the default is a variable named CASE_LBL, if it exists.
If it does not then the variables created by FLIP are named VAR000
there are no remaining possibilities. If the latter occurs then the
FLIP operation aborts.
-The resultant dictionary contains a CASE_LBL variable, which stores the
-names of the variables in the dictionary before the transposition. If
-the active file is subsequently transposed using @cmd{FLIP}, this
-variable can
-be used to recreate the original variable names.
+The resultant dictionary contains a CASE_LBL variable, a string
+variable of width 8, which stores the names of the variables in the
+dictionary before the transposition. Variables names longer than 8
+characters are truncated. If the active file is subsequently
+transposed using @cmd{FLIP}, this variable can be used to recreate the
+original variable names.
FLIP honors @cmd{N OF CASES} (@pxref{N OF CASES}). It ignores
@cmd{TEMPORARY} (@pxref{TEMPORARY}), so that ``temporary''
for ascending order. These apply to the entire list of variables
preceding them.
+The sort algorithms used by @cmd{SORT CASES} are stable. That is,
+records that have equal values of the sort variables will have the
+same relative order before and after sorting. As a special case,
+re-sorting an already sorted file will not affect the ordering of
+cases.
+
@cmd{SORT CASES} is a procedure. It causes the data to be read.
@cmd{SORT CASES} attempts to sort the entire active file in main memory.
-If main memory is exhausted, it falls back to a merge sort algorithm that
-involves writing and reading numerous temporary files.
+If workspace is exhausted, it falls back to a merge sort algorithm that
+involves creates numerous temporary files.
@cmd{SORT CASES} may not be specified following TEMPORARY.
@setfilename ignored