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Matlab, nested functions, and variables

I rejoiced that MATLAB lets you have locally declared functions. Ahh, where are Python's namespaces? All hail Python. Fie promiscuous MATLAB! poor shadow, false pretender.. ahem..

Ok, so I go and nest a function and load some data from a file and Boom! MATLAB cries Uncle, with some wimpy excuse that it can't load variables into a static workspace. I ask you, is that grown up behavior?

So I have to do this round about thing: Suppose I have a mat file segmenting.mat with 6 variables called segment, dive_trials, dive_segment, trials, interaction, and capture. I have to load them into an explicit variable (thisisbogus) and then I have them as structure fields. Ewww.

thisisbogus = load('segmenting')

thisisbogus =

segment: [43x2 double]
dive_trials: [2 3 4 5 7 8 9 10 12 16 19 20 26 29 32 38 39 41 43]
dive_segment: [19x2 double]
trials: [1x38 double]
interaction: [43x1 double]
capture: [43x1 double]

I didn't want to type the bazillion lines of code to assign each field back to a variable, so I automated it

thisisbogus = load('segmenting')
bog = fieldnames(thisisbogus)
for n=1:length(bog),
disp([bog{n} ' = getfield(thisisbogus,bog{' num2str(n) '});'])
end

which prints

segment = getfield(thisisbogus,bog{1});
dive_trials = getfield(thisisbogus,bog{2});
dive_segment = getfield(thisisbogus,bog{3});
trials = getfield(thisisbogus,bog{4});
interaction = getfield(thisisbogus,bog{5});
capture = getfield(thisisbogus,bog{6});

Which can be pasted into the MATLAB function.

I get this nagging feeling that MathWorks is getting sloppy, I wonder why. This makes me upset, just like Microsoft Word's half-baked implementation of a cross-referencing system.

Then why don't I just go use Python and Latex then, you say? I do, I do, but JEB prefers Word files, and my co-authors use MATLAB and Word...
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Comments

  1. AnonymousFebruary 19, 2008 at 3:37 PM

    FYI, you don't have to copy and paste that output to do your reassignment. You can execute the commands directly in your loop if you just change the "disp" to an "eval".

    ReplyDelete
  2. Kaushik GhoseFebruary 19, 2008 at 3:43 PM

    Unfortunately, no. The evals will require MATLAB to generate variables on the fly, which it can not do in nested functions (aka static workspaces)

    ReplyDelete
  3. AnonymousFebruary 21, 2008 at 4:04 PM

    Good point. How about an "evalin('caller',..." then? I got it to work as follows:

    function output=nestTest()
    nest()
    function []=nest()
    for i = 0:25
    evalin('caller',['output.','a'+i,'=',num2str(i),';'])
    end
    end
    end


    Yielding:

    >> nestTest()
    ans =
    a: 0
    b: 1
    c: 2 ...

    ReplyDelete

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