9.6 SAVE

SAVE
        /OUTFILE={’file_name’,file_handle}
        /UNSELECTED={RETAIN,DELETE}
        /{UNCOMPRESSED,COMPRESSED,ZCOMPRESSED}
        /PERMISSIONS={WRITEABLE,READONLY}
        /DROP=var_list
        /KEEP=var_list
        /VERSION=version
        /RENAME=(src_names=target_names)…
        /NAMES
        /MAP

The SAVE procedure causes the dictionary and data in the active dataset to be written to a system file.

OUTFILE is the only required subcommand. Specify the system file to be written as a string file name or a file handle (see File Handles).

By default, cases excluded with FILTER are written to the system file. These can be excluded by specifying DELETE on the UNSELECTED subcommand. Specifying RETAIN makes the default explicit.

The UNCOMPRESSED, COMPRESSED, and ZCOMPRESSED subcommand determine the system file’s compression level:

UNCOMPRESSED

Data is not compressed. Each numeric value uses 8 bytes of disk space. Each string value uses one byte per column width, rounded up to a multiple of 8 bytes.

COMPRESSED

Data is compressed with a simple algorithm. Each integer numeric value between -99 and 151, inclusive, or system missing value uses one byte of disk space. Each 8-byte segment of a string that consists only of spaces uses 1 byte. Any other numeric value or 8-byte string segment uses 9 bytes of disk space.

ZCOMPRESSED

Data is compressed with the “deflate” compression algorithm specified in RFC 1951 (the same algorithm used by gzip). Files written with this compression level cannot be read by PSPP 0.8.1 or earlier or by SPSS 20 or earlier.

COMPRESSED is the default compression level. The SET command (see SET) can change this default.

The PERMISSIONS subcommand specifies permissions for the new system file. WRITEABLE, the default, creates the file with read and write permission. READONLY creates the file for read-only access.

By default, all the variables in the active dataset dictionary are written to the system file. The DROP subcommand can be used to specify a list of variables not to be written. In contrast, KEEP specifies variables to be written, with all variables not specified not written.

Normally variables are saved to a system file under the same names they have in the active dataset. Use the RENAME subcommand to change these names. Specify, within parentheses, a list of variable names followed by an equals sign (‘=’) and the names that they should be renamed to. Multiple parenthesized groups of variable names can be included on a single RENAME subcommand. Variables’ names may be swapped using a RENAME subcommand of the form /RENAME=(A B=B A).

Alternate syntax for the RENAME subcommand allows the parentheses to be eliminated. When this is done, only a single variable may be renamed at once. For instance, /RENAME=A=B. This alternate syntax is deprecated.

DROP, KEEP, and RENAME are performed in left-to-right order. They each may be present any number of times. SAVE never modifies the active dataset. DROP, KEEP, and RENAME only affect the system file written to disk.

The VERSION subcommand specifies the version of the file format. Valid versions are 2 and 3. The default version is 3. In version 2 system files, variable names longer than 8 bytes are truncated. The two versions are otherwise identical.

The NAMES and MAP subcommands are currently ignored.

SAVE causes the data to be read. It is a procedure.