Adding columns to tables

Asked by IE on 18 Jul 2019

Latest activity Commented on by Adam Danz on 18 Jul 2019

4 views (last 30 days)

I'm trying to loop through a list of file names such that I grab a column from a particular file and put it into the first empty column in a table, which I then write to a text file. What happens instead is that instead of adding the column to the end, it changes every existing column in the table. Code below. Any fixes?

clear
clc
% Names of variables to be sorted into individual files
nNames=["Trunk_Fwd_Tilt";"Trunk_Lat_Tilt";"Trunk_Rotation";"Pelvis_Fwd_Tilt";"Pelvis_Lat_Tilt";"Pelvis_Rotation";"R_HIPFlexANG";"R_HIPAbdANG";"R_HIPRotANG";"R_KNEEFlexANG";"R_KNEEAbdANG";"R_KNEERotANG";"R_ANKFlexANG";"R_Foot_Orientation";"R_Shl_Flex_Ang";"L_HIPFlexANG";"L_HIPAbdANG";"L_HIPRotANG";"L_KNEEFlexANG";"L_KNEEAbdANG";"L_KNEERotANG";"L_ANKFlexANG";"L_Foot_Orientation";"L_Shl_Flex_Ang";"R_KNEEPWR";"R_ANKPWR";"L_HIPPWR";"L_KNEEPWR";"L_ANKPWR"];
pName=["Trunk Tilt","Trunk Obliquity","Trunk Rotation","Pelvic Tilt","Pelvic Obliquity","Pelvic Rotation","Hip Flexion/Extension","Hip Ad/Abduction","Hip Rotation","Knee Flexion/Extension","Knee Varus/Valgus","Knee Rotation","Ankle Dorsi/Plantar","Foot Progress wrt Room","Shank Rotation"];
% Scan for names of all norm files
direc=["EXAMPLE NAME","EXAMPLE NAME","EXAMPLE NAME"];
fileID=fopen(EXAMPLE NAME,'w');
pasteTable=table();
%Make file containing all the file names we want from each directory
for tInc=20:30
        sFind=strcat("_hss_",num2str(tInc));
        for dirInc=1:3
            dirInfo=dir(direc(dirInc));
            structSize=(size(dirInfo));
            for nInc=1:structSize(1)
                dirName=dirInfo(nInc).name;
                pHold=string(dirName);
                if contains(pHold,sFind)
                    %Append folder name to file name
                    pHold=strcat(direc(dirInc),pHold);
                    fprintf(fileID,'%s\n',pHold);
                end
                
            end
        end
end
%Read the table back in
opts=delimitedTextImportOptions('LineEnding','\n');
dirNames=readtable('EXAMPLE NAME',opts);
%Increment through file names
for nInc=1:height(dirNames)
    dest=dirNames.Var1(nInc);
    dest=char(dest);
    [nOutTable,topCol]=Norm2Tab(dest);
    %Incrementing through all names of variables
    for i=1:length(nNames)
        vName=nNames(i);
        fName=strcat('EXAMPLE NAME',vName,'.txt');
        fileID2=fopen(fName,'w');
        %Incrementing through all file names
        for j=1:height(dirNames)
            pHold=nOutTable(1:100,vName);
            cName=char(strcat("Var"+j));
            pHold.Properties.VariableNames={cName};
            pasteTable=[pasteTable pHold]
            
        end
        writetable(pasteTable,fName,'WriteVariableNames',false);
    end
end

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2 Answers

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Answer by Adam Danz on 18 Jul 2019

Edited by Adam Danz on 18 Jul 2019

Accepted Answer

Try saving all tables to a cell array and then concatenating them after the loop.

        %Incrementing through all file names
        C = cell(1,height(dirNames)); 
        for j=1:height(dirNames)
            pHold=nOutTable(1:100,vName);
            cName=char(strcat("Var"+j));
            pHold.Properties.VariableNames={cName};
            C{i} = pHold; % Each column must have a unique variable name!        
        end
        pasteTable = [C{:}];  % Concatenate

Note: I didn't comb through your code to figure out why your current method is not working. Any existing problems may also affect the method I recommended. If the problem persists, please attach the necessary files so we can run your code.

2 Comments

IE on 18 Jul 2019

As it turned out, I'd hardcoded the file name in Norm2Tab, so it ran that regardless of the file destination I put in, but this method did work once I fixed it. Thanks!

Adam Danz on 18 Jul 2019

Good find! Glad I could help.

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Answer by David K. on 18 Jul 2019

Check out https://www.mathworks.com/help/matlab/matlab_prog/add-and-delete-table-variables.html if you have not.

It has many ways that you can add columns to a table. Picking out a few that I think may be useful to you-

If you want to replace or make a new column and you know the name of the column you can do

Table.ColName = ColMatrix;

If you want to append the columns to the end you can do it like this

newCol = table(ColMatrix);
Table = [Table newCol];

You are now following this question

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