Non-existing values in the Plot

Question

Pedro 2014-9-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/154310-non-existing-values-in-the-plot

评论： Pedro 2014-9-10

try.txt

Greetings. I'm having trouble with some code. This function should display a curve based on X and Y values loaded from a .txt file. For some reason, when it displays the curve it also draws a line in the Y axis. At first I thought I had a problem with the .txt, but i tried plotting it in excel and the curve appears as it should. Also, this does not happen with all the .txt files I'm working with.

Code

       function graph
      clc;
      set(0,'DefaultFigureColor','w',...
            'DefaultAxesColor','w',...
            'DefaultAxesXColor','k',...
            'DefaultAxesYColor','k',...
            'DefaultAxesZColor','k',...
            'DefaultTextColor','k',...
            'DefaultLineColor','k');
      x = load('try.txt');
      r1 = load('try.txt');
      r1 = r1(:,2);
      f1=figure(1); 
      clf;
      get(f1);
      set(f1,'Units','centimeters','Position',[3 3 24 14]);
      axes1 = axes('Parent',f1,'FontWeight','bold','FontSize',14,'Ygrid', 'on','grid', ':','Position',[0.15 0.2 0.8 0.7]);
      set(gcf,'Color',[1,1,1]);
      box on;
      hold on;
axis([0, 16,  0, 6e+06]);
plot(x, r1, '-g','LineWidth',2,'Marker','none', 'Markersize', 5);
hold on
end

This is what my code generates:

This is what excel draws (and what it should be):

Any ideas?

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Answer 1

the cyclist 2014-9-10

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/154310-non-existing-values-in-the-plot#answer_151312

在 MATLAB Online 中打开

Your x variable is both columns of the input file, and r1 is only the second column.

I think you are unintentionally plotting both columns of the input against the second, when you intended to plot the first against the second. The following give what you want:

plot(x(:,1), r1, '-g','LineWidth',2,'Marker','none', 'Markersize', 5);

The following is even better, dispensing with your loading the file twice:

        clc;
        set(0,'DefaultFigureColor','w',...
              'DefaultAxesColor','w',...
              'DefaultAxesXColor','k',...
              'DefaultAxesYColor','k',...
              'DefaultAxesZColor','k',...
              'DefaultTextColor','k',...
              'DefaultLineColor','k');
        x = load('try.txt');
        f1=figure(1); 
        clf;
        get(f1);
        set(f1,'Units','centimeters','Position',[3 3 24 14]);
        axes1 = axes('Parent',f1,'FontWeight','bold','FontSize',14,'Ygrid', 'on','grid', ':','Position',[0.15 0.2 0.8 0.7]);
        set(gcf,'Color',[1,1,1]);
        box on;
        hold on;
  axis([0, 16,  0, 6e+06]);
  plot(x(:,1), x(:,2), '-g','LineWidth',2,'Marker','none', 'Markersize', 5);
  hold on