Check for existence of mat-file in search path

Question

dm 2012-5-8

1
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https://ww2.mathworks.cn/matlabcentral/answers/37722-check-for-existence-of-mat-file-in-search-path

评论： Henrik 2016-7-6

Just came over an "interesting" problem. If I run exist('mandrill','file'), I get false back, which I normally would interpret as the (mat)file doesn't exist in the Matlab search path. However, imgdata=load('mandrill') works perfectly fine. Same applies for the 'seamount' image (or any other images that come along with Matlab/toolboxes).

How come Matlab knows where to look for the file/data when using load() and not when using exist()? Problem is that I'd like to have a test similar to

if ~exist('mandrill')
    bla bla bla;
    return;
else
    bla bla bla;
    return;
end

But at the moment this won't work. Any suggestions for how to solve this?

If it should matter I use Matlab R2012a.

Best regards, dm

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Henrik 2016-7-6

Could be because "exist" is looking for a .m file when you don't specify the fileformat. If you instead write ~exist('mandrill.mat','file') it should work.

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Answer 1

dm 2012-5-8

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/37722-check-for-existence-of-mat-file-in-search-path#answer_47056

Always too fast to ask. Seems like just adding the extension works fine, e.g. exist('mandrill.mat') returns 2.

See comment field at http://blogs.mathworks.com/loren/2006/02/01/existence-in-matlab/ for reference.

Problem solved.

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Jan 2012-5-8

It is recommended to specify the 2nd parameter for EXIST in every case. Otherwise EXIST could be very slow and the result can be surprising, e.g. if you have a folder of the same name.

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