how to remove zeroes from the end of column in a matrice

Question

Dolev 2023-5-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1969539-how-to-remove-zeroes-from-the-end-of-column-in-a-matrice

评论： Walter Roberson 2023-5-22

hi

i have wrritten this codes that proces data from excel file, the data file is of measurments.

[app.filenameZT,pathname] = uigetfile({'*.xls';'*.xlsx'},MultiSelect="on");
app.C=iscell(app.filenameZT(1,2));
if app.C==1
    app.LengthZT=length(app.filenameZT);
else
    app.LengthZT=1;
end
if app.C==1
    for i=1:numel(app.filenameZT)
        ZT(i)=importdata(fullfile(pathname,app.filenameZT{i}));
        app.t(1:length(ZT(i).data(:,1)),i)=ZT(i).data(:,1);
        app.S(1:length(ZT(i).data(:,2)),i)=ZT(i).data(:,2);
        app.R(1:length(ZT(i).data(:,3)),i)=ZT(i).data(:,3).*10^(6);
        app.K(1:length(ZT(i).data(:,4)),i)=ZT(i).data(:,4);
        app.zT(1:length(ZT(i).data(:,5)),i)=ZT(i).data(:,5);
      
    end
else
    ZT=importdata(fullfile(pathname,app.filenameZT));
    app.t=ZT.data(:,1);
    app.S=ZT.data(:,2);
    app.R=ZT.data(:,3);
    app.K=ZT.data(:,4);
    app.zT=ZT.data(:,5);
end
if app.C==1
    figure (1)
    plot(app.t,app.S,'linewidth',2);
    hold on
    for i=1:numel(app.filenameZT)
    plot(app.t(i),app.S(i),'linewidth',2);
    end
    title('Seebeck Coefficient','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel ('\alpha[\muV/K]','fontweight','bold','fontsize',22)
    legend (app.filenameZT);
    grid minor
    hold off
    %ploting ressetivity
    figure (2)
    plot(app.t,app.R,'linewidth',2);
    hold on
    for i=1:numel(app.filenameZT)
    plot(app.t(i),app.R(i),'linewidth',2);
    end
    title('Electrical Resistivity','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel('\rho[\mu\Omega*cm]','fontweight','bold','fontsize',22)
    grid minor
    legend (app.filenameZT);
    hold off
    figure (3)%% ploting kappa
    plot(app.t,app.K,'linewidth',2);
    hold on
    for i=1:numel(app.filenameZT)
    plot(app.t(i),app.K(i),'linewidth',2);
    end
    title('Thermal Conductivity','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel('\kappa[W/cm*C]','fontweight','bold','fontsize',22)
    grid minor
    legend (app.filenameZT);
    hold off
    figure (4)%% ploting zT
    plot(app.t,app.zT,'linewidth',2);
    hold on
    for i=1:numel(app.filenameZT)
    plot(app.t(i),app.zT(i),'linewidth',2);
    end
    title('Figure of Merit zT','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel('zT','fontweight','bold','fontsize',22)
    grid minor
    legend (app.filenameZT);
    hold off
else
     figure (1)
    plot(app.t,app.S,'color','b','linewidth',2);
    hold on
    plot(app.t,app.S,'color','r','linewidth',2);
    title('Seebeck Coefficient','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel ('\alpha[\muV/K]','fontweight','bold','fontsize',22)
    legend (app.filenameZT);
    grid minor
    hold off
    %ploting ressetivity
    figure (2)
    plot(app.t,app.R,'color','b','linewidth',2);
    hold on
    plot(app.t,app.R,'color','r','linewidth',2);
    title('Electrical Resistivity','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel('\rho[\mu\Omega*cm]','fontweight','bold','fontsize',22)
    grid minor
    legend (app.filenameZT);
    hold off
    figure (3)%% ploting kappa
    plot(app.t,app.K,'color','b','linewidth',2);
    hold on
    plot(app.t,app.K,'color','r','linewidth',2);
    title('Thermal Conductivity','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel('\kappa[W/cm*C]','fontweight','bold','fontsize',22)
    grid minor
    legend (app.filenameZT);
    hold off
    figure (4)%% ploting zT
    plot(app.t,app.zT,'color','b','linewidth',2);
    hold on
    plot(app.t,app.zT,'color','r','linewidth',2);
    title('Figure of Merit zT','fontweight','bold','fontsize',22)
    xlabel('T[C]','fontweight','bold','fontsize',22)
    ylabel('zT','fontweight','bold','fontsize',22)
    grid minor
    legend (app.filenameZT);
    hold off
end

the problem is that not all the file have the same length of data, so what happens is that in the end of the shorter length data zeroes are add, how can i delete those zeroes at the end of the columns?

files to use the code are attached

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Answer 1

Walter Roberson 2023-5-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1969539-how-to-remove-zeroes-from-the-end-of-column-in-a-matrice#answer_1240844

在 MATLAB Online 中打开

after the importdata,

lastused = find(any(zT(i).Data,2),1,'last');
zT(i).Data = zT(i).Data(1:lastused,:);

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Dolev 2023-5-22

ok that works but i still get zeros when i plot the data with the apllied range

Walter Roberson 2023-5-22

If different columns have different number of trailing 0 and you want to trim each one independently to remove the trailing 0, then unless you replace the values with something else (such as nan) you cannot store the result as a table() object. It also appear to me that your plotting would give you problems, unless you trimmed down t for each variable indepdently.

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