-@node Data Manipulation, Data Selection, Variable Attributes, Top
+@node Data Manipulation
@chapter Data transformations
@cindex transformations
* SORT CASES:: Sort the active file.
@end menu
-@node AGGREGATE, AUTORECODE, Data Manipulation, Data Manipulation
+@node AGGREGATE
@section AGGREGATE
@vindex AGGREGATE
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. The MEAN, SD, and SUM aggregation functions may only be
+variable. The MEAN, MEDIAN, 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.
+and string variables.
The available aggregation functions are as follows:
Arithmetic mean. Limited to numeric values. The default format is
F8.2.
+@item MEDIAN(var_name)
+The median value. Limited to numeric values. The default format is F8.2.
+
@item MIN(var_name)
Minimum value. The aggregation variable receives the complete
dictionary information from the source variable.
@cmd{AGGREGATE} both ignores and cancels the current @cmd{SPLIT FILE}
settings (@pxref{SPLIT FILE}).
-@node AUTORECODE, COMPUTE, AGGREGATE, Data Manipulation
+@node AUTORECODE
@section AUTORECODE
@vindex AUTORECODE
@cmd{AUTORECODE} is a procedure. It causes the data to be read.
-@node COMPUTE, COUNT, AUTORECODE, Data Manipulation
+@node COMPUTE
@section COMPUTE
@vindex COMPUTE
@cmd{COMPUTE} assigns the value of an expression to a target
variable. For each case, the expression is evaluated and its value
-assigned to the target variable. Numeric and short and long string
+assigned to the target variable. Numeric and string
variables may be assigned. When a string expression's width differs
from the target variable's width, the string result of the expression
is truncated or padded with spaces on the right as necessary. The
(@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
(@pxref{LAG}).
-@node COUNT, FLIP, COMPUTE, Data Manipulation
+@node COUNT
@section COUNT
@vindex COUNT
The target variable values are always nonnegative integers. They are
never missing. The target variable is assigned an F8.2 output format.
-@xref{Input/Output Formats}. Any variables, including long and short
+@xref{Input and Output Formats}. Any variables, including
string variables, may be test variables.
User-missing values of test variables are treated just like any other
@end example
@end enumerate
-@node FLIP, IF, COUNT, Data Manipulation
+@node FLIP
@section FLIP
@vindex FLIP
@cmd{TEMPORARY} (@pxref{TEMPORARY}), so that ``temporary''
transformations become permanent.
-@node IF, RECODE, FLIP, Data Manipulation
+@node IF
@section IF
@vindex IF
following the IF keyword. This expression is evaluated for each case.
If the value is true, then the value of the expression is computed and
assigned to the specified variable. If the value is false or missing,
-nothing is done. Numeric and short and long string variables may be
+nothing is done. Numeric and string variables may be
assigned. When a string expression's width differs from the target
variable's width, the string result of the expression is truncated or
padded with spaces on the right as necessary. The expression and
(@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
(@pxref{LAG}).
-@node RECODE, SORT CASES, IF, Data Manipulation
+@node RECODE
@section RECODE
@vindex RECODE
@cmd{RECODE} translates data from one range of values to
another, via flexible user-specified mappings. Data may be remapped
-in-place or copied to new variables. Numeric, short string, and long
+in-place or copied to new variables. Numeric and
string data can be recoded.
Specify the list of source variables, followed by one or more mapping
system missing value only. ELSE is a catch-all that matches anything.
It should be the last src_value specified.
-Numeric and string dest_value's should also be self-explanatory. COPY
-causes the input values to be copied to the output. This is only value
+Numeric and string dest_value's should be self-explanatory. COPY
+causes the input values to be copied to the output. This is only valid
if the source and target variables are of the same type. SYSMIS
indicates the system-missing value.
Introduce additional recodings with a slash (@samp{/}) to
separate them from the previous recodings.
-@node SORT CASES, , RECODE, Data Manipulation
+@node SORT CASES
@section SORT CASES
@vindex SORT CASES
@display
-SORT CASES BY var_list.
+SORT CASES BY var_list[(@{D|A@}] [ var_list[(@{D|A@}] ] ...
@end display
@cmd{SORT CASES} sorts the active file by the values of one or more
Specify BY and a list of variables to sort by. By default, variables
are sorted in ascending order. To override sort order, specify (D) or
(DOWN) after a list of variables to get descending order, or (A) or (UP)
-for ascending order. These apply to the entire list of variables
-preceding them.
+for ascending order. These apply to all the listed variables
+up until the preceding (A), (D), (UP) or (DOWN).
The sort algorithms used by @cmd{SORT CASES} are stable. That is,
records that have equal values of the sort variables will have the
involves creates numerous temporary files.
@cmd{SORT CASES} may not be specified following TEMPORARY.
-@setfilename ignored
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