From d1bc9c2bfd03aabfd8c00f520b8395b3c07faf69 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Sun, 13 Mar 2005 07:21:14 +0000 Subject: [PATCH] Clarify AGGREGATE. --- doc/transformation.texi | 47 ++++++++++++++++++++++------------------- 1 file changed, 25 insertions(+), 22 deletions(-) diff --git a/doc/transformation.texi b/doc/transformation.texi index b0cdccb6..b89edb0d 100644 --- a/doc/transformation.texi +++ b/doc/transformation.texi @@ -22,12 +22,12 @@ as a rule. @vindex AGGREGATE @display -AGGREGATE - /BREAK=var_list +AGGREGATE + OUTFILE=@{*,'filename'@} /PRESORTED - /OUTFILE=@{*,'filename'@} /DOCUMENT /MISSING=COLUMNWISE + /BREAK=var_list /dest_var['label']@dots{}=agr_func(src_vars, args@dots{})@dots{} @end display @@ -36,26 +36,35 @@ Cases are divided into groups that have the same values for one or more variables called @dfn{break variables}. Several functions are available for summarizing case contents. -At least one break variable must be specified on BREAK, the only -required subcommand. The values of these variables are used to divide -the active file into groups to be summarized. In addition, at least -one @var{dest_var} must be specified. +The OUTFILE subcommand is required and must appear first. Specify a +system file by file name string or file handle (@pxref{FILE HANDLE}). +The aggregated cases are written to this file. If @samp{*} is +specified, then the aggregated cases replace the active file. -By default, the active file is sorted based on the break variables +By default, the active file will be sorted based on the break variables before aggregation takes place. If the active file is already sorted or otherwise grouped in terms of the break variables, specify PRESORTED to save time. -The OUTFILE subcommand specifies a system file by file name string or -file handle (@pxref{FILE HANDLE}). The aggregated cases are written to -this file. If OUTFILE is not specified, or if @samp{*} is specified, -then the aggregated cases replace the active file. - Specify DOCUMENT to copy the documents from the active file into the aggregate file (@pxref{DOCUMENT}). Otherwise, the aggregate file will not contain any documents, even if the aggregate file replaces the active file. +Normally, only a single case (for SD and SD., two cases) need be +non-missing in each group for the aggregate variable to be +non-missing. Specifying /MISSING=COLUMNWISE inverts this behavior, so +that the aggregate variable becomes missing if any aggregated value is +missing. + +If PRESORTED, DOCUMENT, or MISSING are specified, they must appear +between OUTFILE and BREAK. + +At least one break variable must be specified on BREAK, a +required subcommand. The values of these variables are used to divide +the active file into groups to be summarized. In addition, at least +one @var{dest_var} must be specified. + One or more sets of aggregation variables must be specified. Each set comprises a list of aggregation variables, an equals sign (@samp{=}), the name of an aggregation function (see the list below), and a list @@ -72,9 +81,9 @@ list. Each set must have exactly as many source variables as aggregation variables. Each aggregation variable receives the results of applying the specified aggregation function to the corresponding source -variable. Most aggregation functions may be applied to numeric and -short and long string variables. Others, marked below, are restricted -to numeric values. +variable. The MEAN, SD, and SUM aggregation functions may only be +applied to numeric variables. All the rest may be applied to numeric +and short and long string variables. The available aggregation functions are as follows: @@ -173,12 +182,6 @@ from calculations. To include user-missing values, insert a period (@samp{.}) between the function name and left parenthesis (e.g.@: @samp{SUM.}). -Normally, only a single case (for SD and SD., two cases) need be -non-missing in each group for the aggregate variable to be -non-missing. Specifying /MISSING=COLUMNWISE inverts this behavior, so -that the aggregate variable becomes missing if any aggregated value is -missing. - @cmd{AGGREGATE} both ignores and cancels the current @cmd{SPLIT FILE} settings (@pxref{SPLIT FILE}). -- 2.30.2