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Chapter 9: System and Portable File I/O
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/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 Section 6.9 [File Handles], page 44).
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 Section 16.20
[SET], page 157) 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.