For loop update matrix

Question

Victor 2014-6-6

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/132721-for-loop-update-matrix

评论： Star Strider 2014-6-6

采纳的回答： Star Strider

In my for loop i want to create and append the elements in a column vector everytime i run the function.

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Answer 1

Star Strider 2014-6-6

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/132721-for-loop-update-matrix#answer_139655

在 MATLAB Online 中打开

From my previous Answer to your similar question:

for k2 = 1:2                            % Simulate two function calls
    a = 30;                             % Input argument
    b = 400;                            % Input argument
    k1i = 0;                            % First line of actual function
    filex = 0;                          % File doesn’t exist at first
    filename = 'input_data_file.mat';
    if exist(filename,'file')           % If file exists, load it
        load(filename)
        k1i = mtrx(end,1);              % Find previous end index value
        filex = 1;
    end
    for k1 = k1i+1:(k1i+a)              % Loop to create this version of ‘mtrx’
        mtrx(k1,:) = [k1  b];
    end
    if filex == 1                       % If file exists, append to it, if not create it
        save(filename, 'mtrx', '-append')
    elseif filex == 0
        save(filename, 'mtrx')
    end                                 % Last line of function (other than its own ‘end’ statement)
    fout = fopen('input_data_textfile.txt', 'w+');
    fprintf(fout, '%d  ', mtrx')        % Write text file
end

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Star Strider 2014-6-6

在 MATLAB Online 中打开

The code as an example function:

function mtx = matfileappend(a,b)
    k1i = 0;                            % First line of actual function
    filex = 0;                          % File doesn’t exist at first
    filename = 'input_data_file.mat';
    if exist(filename,'file')           % If file exists, load it
        load(filename)
        k1i = mtrx(end,1);              % Find previous end index value
        filex = 1;
    end
    for k1 = k1i+1:(k1i+a)              % Loop to create this version of ‘mtrx’
        mtrx(k1,:) = [k1  b];
    end
    if filex == 1                       % If file exists, append to it, if not create it
        save(filename, 'mtrx', '-append')
    elseif filex == 0
        save(filename, 'mtrx')
    end                                 % Last line of function (other than its own ‘end’ statement)
    mtx = mtrx;                         % Returns accumulated matrix ‘mtrx’ as output
end

If you want to write the text file, you could do that inside or outside the function. I omitted it from the function because it’s not necessary there. This also assumes the file name for the mat-file never changes, and is always a part of the function. You could add it as an argument if you want, but that would require some minor changes in the code to define it as the ‘filename’ variable.

The function statement (first line, declaring it as a function) can be change to do what you want it to.

Victor 2014-6-6

For those plots, how do i control the spacing if i were to use the subplot function?

Star Strider 2014-6-6

I saw your Question on that and submitted an Answer. It has been the subject of several recent posts here, so I referred you to the best of those. There are also several topics in the Examples section of the documentation page for subplot.

The idea is to use the 'Position' property in each subplot and adjust it individually for each subplot.

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