MATLAB: How to save all global variables

global variablessave workspace

The save command only saves those Matlab variables which are visible in a workspace. It does not, however, cover the global variables which are reported by who('global') but have not been declared as globals in this workspace. Is there a way to save all global variables in a given Matlab session, even if their names are not known a priori?

Best Answer

While I recommend not to use global variables, because they impede the debugging dramatically, there should be a solution to your problem.
When you want to save the variables, which are found by who('global'), it would be a simple idea to use globalVars = who('global') to get a list of these variables at first. Then the values might not be known inside a function. So, sigh, I have to suggest to one and only case, which I cannot solve without eval.
globalVars = who('global');
for iVar = 1:numel(globalVars)
  eval(sprintf('global %s', globalVars{iVar}));  % [EDITED]
end
This can overwrite local variables by accident, e.g. if "globalVars" is a global variable itself, this approach is buggy. Therefore I strongly recommend to choose a different strategy. The complexity caused by the automatic access of global variables cannot be managed reliably. And when there is the decision between a complicated and inherently buggy method and a clean and clear one, <not every sentence has to be finished>
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