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The save
and load
commands allow data to be written to and
read from disk files in various formats. The default format of files
written by the save
command can be controlled using the built-in
variables default_save_options
and save_precision
.
Note that Octave cannot yet save or load structure variables or any user-defined types.
Save the named variables v1, v2, ... in the file file. The special filename `-' can be used to write the output to your terminal. If no variable names are listed, Octave saves all the variables in the current scope. Valid options for the
save
command are listed in the following table. Options that modify the output format override the format specified by the built-in variabledefault_save_options
.
-ascii
- Save the data in Octave's text data format.
WARNING: the meaning of this option will change in a future version of Octave to be compatible with Matlab. To keep the meaning of your code the same across this change, use the
-text
option instead.-binary
- Save the data in Octave's binary data format.
-float-binary
- Save the data in Octave's binary data format but only using single precision. You should use this format only if you know that all the values to be saved can be represented in single precision.
-V7
-v7
-7
-mat7-binary
- Save the data in Matlab's v7 binary data format.
-V6
-v6
-6
-mat
-mat-binary
- Save the data in Matlab's v6 binary data format.
-V4
-v4
-4
-mat4-binary
- Save the data in the binary format written by Matlab version 4.
-hdf5
- Save the data in HDF5 format. (HDF5 is a free, portable binary format developed by the National Center for Supercomputing Applications at the University of Illinois.)
-float-hdf5
- Save the data in HDF5 format but only using single precision. You should use this format only if you know that all the values to be saved can be represented in single precision.
-save-builtins
- Force Octave to save the values of built-in variables too. By default, Octave does not save built-in variables.
-zip
-z
- Use the gzip algorithm to compress the file. This works equally on files that are compressed with gzip outside of octave, and gzip can equally be used to convert the files for backward compatibility.
The list of variables to save may include wildcard patterns containing the following special characters:
?
- Match any single character.
*
- Match zero or more characters.
[
list]
- Match the list of characters specified by list. If the first character is
!
or^
, match all characters except those specified by list. For example, the pattern `[a-zA-Z]' will match all lower and upper case alphabetic characters.-text
- Save the data in Octave's text data format.
Except when using the Matlab binary data file format, saving global variables also saves the global status of the variable, so that if it is restored at a later time using `load', it will be restored as a global variable.
The command
save -binary data a b*saves the variable `a' and all variables beginning with `b' to the file data in Octave's binary format.
There are three variables that modify the behavior of save
and
three more that control whether variables are saved when Octave exits
unexpectedly.
If this variable is set to a nonzero value, Octave tries to save all current variables the the file "octave-core" if it crashes or receives a hangup, terminate or similar signal. The default value is 1.
See also: octave_core_file_limit, octave_core_file_name, octave_core_file_options.
If this variable is set to a nonzero value and
crash_dumps_octave_core
is also nonzero, Octave tries to save all current variables the the file "octave-core" if it receives a hangup signal. The default value is 1.
If this variable is set to a nonzero value and
crash_dumps_octave_core
is also nonzero, Octave tries to save all current variables the the file "octave-core" if it receives a terminate signal. The default value is 1.
This variable specifies the default options for the
save
command, and is used to define the default format. Typical values include,"-ascii"
,"-ascii -zip"
. For other possible options see thesave
command. The initial value of this variable is-ascii
.
If Octave aborts, it attempts to save the contents of the top-level workspace in a file using this variable to define the format. The value of
octave_core_file_options
should follow the same format as the options that may be used withsave
. The default value is Octave's binary format.See also: crash_dumps_octave_core, octave_core_file_name, octave_core_file_limit.
This variable specifies the number of digits to keep when saving data in text format. The default value is 17.
This variable specifies the the format string for the comment line that is written at the beginning of text-format data files saved by Octave. The format string is passed to
strftime
and should begin with the character `#' and contain no newline characters. If the value ofsave_header_format_string
is the empty string, the header comment is omitted from text-format data files. The default value is"# Created by Octave VERSION, %a %b %d %H:%M:%S %Y %Z <USER@HOST>"See also: strftime.
Load the named variables from the file file. As with
save
, you may specify a list of variables andload
will only extract those variables with names that match. For example, to restore the variables saved in the file data, use the commandload dataIf a variable that is not marked as global is loaded from a file when a global symbol with the same name already exists, it is loaded in the global symbol table. Also, if a variable is marked as global in a file and a local symbol exists, the local symbol is moved to the global symbol table and given the value from the file. Since it seems that both of these cases are likely to be the result of some sort of error, they will generate warnings.
If invoked with a single output argument, Octave returns data instead of inserting variables in the symbol table. If the data file contains only numbers (TAB- or space-delimited columns), a matrix of values is returned. Otherwise,
load
returns a structure with members corresponding to the names of the variables in the file.The
load
command can read data stored in Octave's text and binary formats, and Matlab's binary format. It will automatically detect the type of file and do conversion from different floating point formats (currently only IEEE big and little endian, though other formats may added in the future).Valid options for
load
are listed in the following table.
-force
- The `-force' option is accepted but ignored for backward compatiability. Octave now overwrites variables currently in memory with the same name as those found in the file.
-ascii
- Force Octave to assume the file is in Octave's text format.
WARNING: the meaning of this option will change in a future version of Octave to be compatible with Matlab. To keep the meaning of your code the same across this change, use the
-text
option instead.-binary
- Force Octave to assume the file is in Octave's binary format.
-mat
-mat-binary
-6
-v6
-7
-v7
- Force Octave to assume the file is in Matlab's version 6 or 7 binary format.
-V4
-v4
-4
-mat4-binary
- Force Octave to assume the file is in the binary format written by Matlab version 4.
-hdf5
- Force Octave to assume the file is in HDF5 format. (HDF5 is a free, portable binary format developed by the National Center for Supercomputing Applications at the University of Illinois.) Note that Octave can read HDF5 files not created by itself, but may skip some datasets in formats that it cannot support.
-import
- The `-import' is accepted but ignored for backward compatiability. Octave can now support multi-dimensional HDF data and automatically modifies variable names if they are invalid Octave identifiers.
-text
- Force Octave to assume the file is in Octave's text format.