MATLAB：用於檢查現有變量的循環

Question

我正在編寫一個腳本，用於運行圖片或樂高並輸出其大小，形狀和顏色。我們編寫腳本的方式，每當我們使用不同樂高的新圖片時，我們都必須清除變量的工作空間。我們必須對我們通過腳本運行的每個樂高進行分類。我們將變量發送到.mat文件，但每次運行腳本時似乎都不能一次保存多個變量，因此保存的變量將被替換爲新值。我已經決定最好的方法是通過循環運行.mat來檢查現有的值，如果有，則將值保存在現有的行下。任何幫助將非常感謝，因爲我是MATLAB新手，尤其是循環。幾天前我問了一個關於這個問題，但決定由於幾個障礙以新的方式處理這個問題。非常感謝。

編輯：

if length > 40 & length < 70 
    y_length = 'Two' 
    area_length = 2 
elseif length > 70 & length < 90 
    y_length = 'Three' 
    area_length = 3 
elseif length > 70 & length < 145 
     y_length = 'Four' 
     area_length = 4 
elseif length > 150 & length < 200 
    y_length = 'Six' 
    area_length = 6 
elseif length < 40 
    y_length = 'One' 
    area_length = 1 
elseif length > 200 
    y_length = 'Eight' 
    area_length = 8 
end 

    if strcmp(x_length,y_length) 
    shape = 'Square' 
else 
    shape = 'Rectangle' 
end 

    size = area_width * area_length ; 

    %%%%%% make sure smaller dimension always first %%%%% 
% width = smaller length 
% length = longer length 

    Cell = {Color, size, shape, x_length, y_length}; 

    % for iterations 1:block_count 
%  if Final = {Color, size, shape, x_length, y_length} 
disp(Cell)  
SaveData = {sprintf('%s, %d, %s, %s, %s', Color, size, shape, x_length, y_length)}; 
% load('Data.mat'); 
% 

    data = [data; SaveData]; 
save('Data.mat', 'SaveData'); 
if length > 40 & length < 70 
     y_length = 'Two' 
     area_length = 2 
    elseif length > 70 & length < 90 
     y_length = 'Three' 
     area_length = 3 
    elseif length > 70 & length < 145 
      y_length = 'Four' 
      area_length = 4 
    elseif length > 150 & length < 200 
     y_length = 'Six' 
     area_length = 6 
    elseif length < 40 
     y_length = 'One' 
     area_length = 1 
    elseif length > 200 
     y_length = 'Eight' 
     area_length = 8 
    end 

    if strcmp(x_length,y_length) 
    shape = 'Square' 
else 
    shape = 'Rectangle' 
end 

    size = area_width * area_length ; 

    %%%%%% make sure smaller dimension always first %%%%% 
% width = smaller length 
% length = longer length 

    Cell = {Color, size, shape, x_length, y_length}; 

    % for iterations 1:block_count 
%  if Final = {Color, size, shape, x_length, y_length} 
disp(Cell)  
SaveData = {sprintf('%s, %d, %s, %s, %s', Color, size, shape, x_length, y_length)}; 
% load('Data.mat'); 
% 

    data = [data; SaveData]; 
save('Data.mat', 'SaveData'); 



                            This is the bottom portion of the script, hopefully enough to give you an idea. Would it be better to change the name of Cell each time it is saved in the .mat file and -append it? Perhaps a loop to recognize the presence of a value in the existing Data.mat and placing it a row below it? 

Answer 1

一種方法是將保存不同的文件不同部分，每個循環的itertion i.e.一個文件。

喜歡的東西：

for k = 1:n 

    % Do your processing here. 
    % Say that the interesting variables are A, B and C. 

    filename = ['Data_' num2str(k, '%06i') '.mat']; 
    save(filename, 'A', 'B', 'C'); 

end 

通過這種方法在其中運行腳本的文件夾將包含n數據文件被稱爲Data_000000.mat，Data_000001.mat，...對應n迭代。

如果你喜歡有一個mat文件，那麼通常最好在循環後只保存一次。例如：

for k = 1:n 

    % Do your processing here. 
    % Say that the interesting variables are A, B and C. 

    A(k) = ....;   
    B(k) = ....; 
    C(k) = ....; 

end 

% Save the results 
save('Data.mat', 'A', 'B', 'C'); 

最佳，

Answer 2

你還是在這艱辛的道路去。如果你有一個你需要處理n圖片列表，添加一個循環，像這樣：

for k = 1:n 
    %// Process picture k, generating newCell 
    %// then append newCell to the end of allCells array 
    allCells(k,:) = newCell; 
end 

現在，如果你還需要將這些保存到一個文件，你可以節省剛allCells，讓您的所有數據立刻。

如果沒有圖像列表事前，你仍然可以通過加載陣列，添加新行，然後再保存它實現你的目標：

load('allCells.mat'); 
%// Process picture, generating newCell 
allCells(end+1,:) = newCell; 
save('allCells.mat',allCells);