How do I load all variables from a MATLAB file except a few specific variables?

When using LOAD, I would like to load all the variables present in the MATLAB file, except for a few specific ones which I do not want to load. Also, when using CLEAR, I would like to be able to clear all variables in the workspace except a few, specific ones which I want to keep.

Answer 1

[MathWorks Support Team]

In each case, regular expressions can be used to operate on all variables except for a short list.

You can use LOAD with the -REGEXP option to specify a regular expression. Suppose 'mydata.mat' contains the following variables:

 myvar1

 variable2

 var

 a

 b

 abcd

 myvar_abc

 data

The following code illustrates several examples:

%%Load all variables except 'var'

load mydata -regexp ^(?!var$).

%%Load all variables except 'a' and 'b'

load mydata -regexp ^(?!a$|b$).

%%Load all variables except 'myvar1', 'myvar_abc', and 'data'

load mydata -regexp ^(?!myvar1$|myvar_abc$|data$).

This idea can be extended to clear all variables from MATLAB's workspace except for a few you do not want to clear. For example, if we have the following variables stored in the workspace:

The = 1;

seed = 2;

of = 3;

the = 4;

tree = 5;

seeds = 25;

aseed = 15;

We can clear all variables except the one named 'seed' by executing the following command:

clear -regexp ^(?!seed$).

Alternatively, we can use the following syntax to clear all variables except for 'seed', 'of', and 'the':

clear -regexp ^(?!seed$|of$|the$).

As of MATLAB 7.6 (R2008a), you can use CLEARVARS with the "-except" flag. For example, the expression

clearvars -except A B

will remove every variable from your workspace except the variables "A" and "B".

You may also use the MATLAB Central file called "keep.m" which provides similar functionality:

 <http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=181>

Note that MathWorks does not guarantee or warrant the use or content of these submissions. Any questions, issues, or complaints should be directed to the contributing author.