For loop iteration help

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ajk1 2016-8-3

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评论： ajk1 2016-8-4

采纳的回答： Geoff Hayes

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Hi, in my code I have

for k=1:20
% code executed with output 'image'
data.(['val' num2str(k)]) = image; % save the dataset in 'data'. Can access data.val1, ... data.val20 
end

I want to write another for loop to go through 'data.val1', going to 'data.val20' to execute another script I have written i.e. for k=1:20 data.val...(value of k for iteration). Help doing this will be appreciated. Thanks.

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ajk1 2016-8-4

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Apologies, this will be my last question here.

I have

for k=51:3:69

Is there a way of removing empty structure fields

I have datasets in S(51).val, S(54).val, ... S(69.val). But not in S(1).val, S(52).val.

I have thought to use number sequences and change 51, 54, 57,...69 to 1, 2, 3, ...7. But later on it will cause confusion with the next part of my script.

ajk1 2016-8-4

Okay, I have solved this. Thanks again!

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Geoff Hayes 2016-8-4

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ajk1 - rather dynamically creating field names for your struct (which is prone to errors), why not just create a (perhaps) cell array to store all of your 20 images in? You can easily iterate over the cell array and extract the image data in your other loop

 data = cell(20,1);
 for k=1:20
    % do something
    data{k} = myImage;  % don't use image which is the name of a built-in MATLAB function
 end

Then, in your other code you would do

 for k=1:length(data)
    myImage = data{k};
    % do something
 end

Try the above and see what happens!

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ajk1 2016-8-4

This works for both the image and the corresponding dataset. For the datasets I changed k=1:numel(data). Thank you!

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Image Analyst 2016-8-4

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Why not have your other processing or loop be a loop inside this one, and not bother about saving all your sub-images in an extra variable (a structure array or cell array)? From what you've told us so far, there is no need to save subimages in an array. Just save them in a single variable and overwrite it each time.

for k = 1 : 20
    % Extract a sub-image.
    subImage = myImage(......
    results(k) = ProcessSubImage(subImage); % Now process it in a function.
end

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ajk1 2016-8-4

Thank you, I am also using this method to store the corresponding image dataset (375x91x223). When I use this method I obtain the error 'Conversion to double from cell is not possible.'

ajk1 2016-8-4