如何在Matlab中將數據輸出到文件？

Question

我讀過幾篇有關如何將數據輸出到文件的文章，但對我來說似乎並不起作用。 我的matlab文件所在的文件夾中有output.txt文件，它只是不向該文件輸出任何數據嗎？

怎么了 我想在單擊圖像時輸出坐標，所以所有輸出邏輯都在偵聽器中。

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

該項目是關於如何在單擊鼠標時獲取坐標以及如何將點坐標輸出到文件的。

Answer 1

首次啟動此文件時，請確保選擇“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，正如Dev-iL所建議的，我添加了添加模式，最終代碼如下所示

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