Is there exist() functionality for packages/namespaces?

22 vues (au cours des 30 derniers jours)
Chris
Chris le 6 Jan 2023
Create a package and put it somewhere in Matlab's path. If you know the parent directory, you could use exist('/path/+package'), but you don't need to know the path to use the package, so that's silly.
The current best solution I have is to try/catch calling a function in the package.

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Ashley Trowell
Ashley Trowell le 26 Oct 2023
There is, but it is hidden. Mathworks doesn't encourage packages and namespaces.
Create this lambda function:
packageExists = @(pkgName) ~isempty(meta.package.fromName(pkgName));
Then run
pkgExist = packageExists('myPkg');
A nice utility is here that just adds the functionality the the exist function, which is what Mathworks should do.

Plus de réponses (1)

Walter Roberson
Walter Roberson le 6 Jan 2023
You can exist() a function inside the package
exist('matlab.internal.lang.capability.Capability')
ans = 8
which matlab.internal.lang.capability.Capability
/MATLAB/toolbox/matlab/capabilities/+matlab/+internal/+lang/+capability/Capability.m % matlab.internal.lang.capability.Capability constructor
You can also which the + form of a function (but not the package itself)
which +matlab/+internal/+lang/+capability/Capability
/MATLAB/toolbox/matlab/capabilities/+matlab/+internal/+lang/+capability/Capability.m % matlab.internal.lang.capability.Capability constructor
which +matlab/+internal/+lang/+capability
'+matlab/+internal/+lang/+capability' not found.
  5 commentaires
Chris
Chris le 7 Jan 2023
Modifié(e) : Chris le 7 Jan 2023
The difference compared to my package would be that the classdef file is not in an @ folder, but in the package root. So it's another example of
exist package.Class
that works.
I wouldn't expect a class method to be available to exist or which (though it turns out they can be found if treated as files), so that just leaves the package itself (I can live without that, I guess), and functions in the +folder--which are the one thing treated differently between which and exist.
Walter Roberson
Walter Roberson le 7 Jan 2023
Class methods can be found using which, but sometimes they will not be located unless the class has been loaded at least once in this session (since the last clear classes)

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