如何輸出數據到matlab文件？

Question

我讀過幾篇關於如何將數據輸出到文件的文章，但它似乎並不適合我。我有我的matlab文件駐留在同一文件夾的output.txt文件，它只是不輸出任何數據到該文件？

它有什麼問題？我想在你點擊圖像時輸出座標，所以所有的輸出邏輯都在監聽器中。

function main 
    clc; close all; 
    % set the range of the axes 
    % The image will be stretched to this. 
    min_x = 0; 
    max_x = 1; 
    min_y = 0; 
    max_y = 1; 

    % replace with an image of your choice 
    img = imread('ryklys.jpg'); 

    imagesc([min_x max_x], [min_y max_y], flipud(img)); 
    hold on; 
    colormap(gray); 

    set(gca,'ydir','normal') 

    cursor_handle = plot(0,0,'r+ ','visible','off') 

    % now attach the function to the axes 
    set(gca,'ButtonDownFcn', @mouseclick_callback) 

    % and we also have to attach the function to the children, in this 
    % case that is the line in the axes. 
    set(get(gca,'Children'),'ButtonDownFcn', @mouseclick_callback) 



    function mouseclick_callback(gcbo,eventdata) 
     % the arguments are not important here, they are simply required for 
     % a callback function. we don't even use them in the function, 
     % but Matlab will provide them to our function, we we have to 
     % include them. 
     % 
     % first we get the point that was clicked on 
     cP = get(gca,'Currentpoint'); 
     x = cP(1,1); 
     y = cP(1,2); 
     % Now we find out which mouse button was clicked, and whether a 
     % keyboard modifier was used, e.g. shift or ctrl 
     switch get(gcf,'SelectionType') 
      case 'normal' % Click left mouse button. 
       s = sprintf('left: (%1.4g, %1.4g) level = %1.4g',x,y, x.*exp(-x.^2-y.^2)); 
      case 'alt' % Control - click left mouse button or click right mouse button. 
       s = sprintf('right: (%1.4g, %1.4g level = %1.4g)',x,y, x.*exp(-x.^2-y.^2)); 
      case 'extend' % Shift - click left mouse button or click both left and right mouse buttons. 
       s = sprintf('2-click: (%1.4g, %1.4g level = %1.4g)',x,y, x.*exp(-x.^2-y.^2)); 
      case 'open' % Double-click any mouse button. 
       s = sprintf('double click: (%1.4g, %1.4g) level = %1.4g',x,y, x.*exp(-x.^2-y.^2)); 
     end 
     % get and set title handle 
     thandle = get(gca,'Title'); 
     set(thandle,'String',s); 
     % finally change the position of our red plus, and make it 
     % visible. 
     set(cursor_handle,'Xdata',x,'Ydata',y,'visible','on') 

     % append file with coordinates 
     plot(x,y,'r.','MarkerSize',20); 

     % Output to file 
     fid=fopen('output.txt','w'); 
     fprintf(fid, '%4.2f %4.2f \n', x, y); 
     fclose(fid); 
    end 
end 

該項目是關於如何獲取圖像鼠標點擊座標和輸出點座標文件。

Answer 1

第一次啓動此文件時，一定要選擇「更改文件夾」，而不是「將文件添加到路徑」。當我選擇「更改文件夾」時，Matlab能夠在'output.txt'文件中寫入數據。 此外，作爲開發金正日建議我加入追加模式，最終的代碼看起來像這樣

function main 
    clc; close all; 
    % Total points counter 
    counter = 0; 

    % set the range of the axes 
    % The image will be stretched to this. 
    min_x = 0; 
    max_x = 1; 
    min_y = 0; 
    max_y = 1; 

    % replace with an image of your choice 
    img = imread('ryklys.jpg'); 

    imagesc([min_x max_x], [min_y max_y], flipud(img)); 
    hold on; 
    colormap(gray); 

    set(gca,'ydir','normal') 

    cursor_handle = plot(0,0,'r+ ','visible','off') 

    % now attach the function to the axes 
    set(gca,'ButtonDownFcn', @mouseclick_callback) 

    % and we also have to attach the function to the children, in this 
    % case that is the line in the axes. 
    set(get(gca,'Children'),'ButtonDownFcn', @mouseclick_callback) 

%  % Output to file 
    outputFile = 'output.txt'; 
    fid=fopen(outputFile,'wt'); 
    fclose(fid); 

    function mouseclick_callback(gcbo,eventdata) 
     % the arguments are not important here, they are simply required for 
     % a callback function. we don't even use them in the function, 
     % but Matlab will provide them to our function, we we have to 
     % include them. 
     % 
     % first we get the point that was clicked on 
     cP = get(gca,'Currentpoint'); 
     x = cP(1,1); 
     y = cP(1,2); 
     % Now we find out which mouse button was clicked, and whether a 
     % keyboard modifier was used, e.g. shift or ctrl 
     switch get(gcf,'SelectionType') 
      case 'normal' % Click left mouse button. 
       s = sprintf('left: (%1.4g, %1.4g) level = %1.4g',x,y, x.*exp(-x.^2-y.^2)); 
      case 'alt' % Control - click left mouse button or click right mouse button. 
       s = sprintf('right: (%1.4g, %1.4g level = %1.4g)',x,y, x.*exp(-x.^2-y.^2)); 
      case 'extend' % Shift - click left mouse button or click both left and right mouse buttons. 
       s = sprintf('2-click: (%1.4g, %1.4g level = %1.4g)',x,y, x.*exp(-x.^2-y.^2)); 
      case 'open' % Double-click any mouse button. 
       s = sprintf('double click: (%1.4g, %1.4g) level = %1.4g',x,y, x.*exp(-x.^2-y.^2)); 
     end 
     % get and set title handle 
     thandle = get(gca,'Title'); 
     set(thandle,'String',s); 
     % finally change the position of our red plus, and make it 
     % visible. 
     set(cursor_handle,'Xdata',x,'Ydata',y,'visible','on') 

     % append file with coordinates 
     plot(x,y,'r.','MarkerSize',20); 

     % Increasing counter value 
     counter = counter + 1; 
     % Printing out points counter value 
     text(x,y, strcat('#', int2str(counter)), 'color', 'r'); 

     % Output to file 
     fid=fopen(outputFile,'at'); 
     fprintf(fid, '%f %f %s %d\n', x, y, '; %', counter); 
     fclose(fid); 
    end 
end