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Often when running long memory expensive programs I want to clear everything but some specific variables. If one wants to delete just some variables clear varA varB can be used, but what about deleting all but this specific variables?

Ander Biguri
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    While `clear` does allow for a regex pattern matching, [`clearvars`](http://www.mathworks.com/help/matlab/ref/clearvars.html) is probably more relevant, particularly the third syntax. – sco1 Jan 08 '16 at 12:05
  • @excaza Wow didnt know about that one! post an answer! – Ander Biguri Jan 08 '16 at 12:07
  • Instead clear your vars whenever you are finished with them. It is a must in Matlab as it doesn't understand functional chains with multiple arguments. – percusse Jan 08 '16 at 13:22
  • @percusse yeah but sometimes I do a level set with 50 cosntarins in aloop, and I want to delete all but the result, as lots of them are mid variables. – Ander Biguri Jan 08 '16 at 13:26
  • @AnderBiguri I hear you loud and clear. Those stuff I tend to push inside a cell and delete the cell afterwards. Mid vars are really super annoying. – percusse Jan 08 '16 at 13:31

2 Answers2

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As mentioned above, clearvars includes a syntax for keeping variables in the workspace while clearing the remainder:

a = 1; b = 1; c = 1; d = 1;
keepvars = {'c', 'd'};

clearvars('-except', keepvars{:});

Which functions as expected.

Like clear, it can also accommodate regexp matching:

a1 = 1; a2 = 1; b = 1; c = 1;
keepvars = 'a\d'; % regex pattern

clearvars('-except', '-regexp', keepvars);

Which retains a1 and a2, as expected.

sco1
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10

Make use of the fact that both who and whos have return values that can be stored in variables. The former returns a cell array of strings, the latter a struct array. For what you need, the former will suffice:

%// don't delete these '
keepvars = {'varA','varB'};

%// delete these
delvars = setdiff(who,keepvars);
clear(delvars{:},'delvars');
rayryeng
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Andras Deak -- Слава Україні
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