Append a row to a workspace table

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Jo Bremer Balestracci 2020-9-29

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https://ww2.mathworks.cn/matlabcentral/answers/602080-append-a-row-to-a-workspace-table

评论： Jo Bremer Balestracci 2020-10-1

I imported a table made in excel into MATLAB and it is now a table in my workspace. The Name is "Configuration" and it is a 1 x 20 table in my workspace. If you open up "Configuration" it looks like this:

>>

1 2 3 4 5 6 7

BookID State noofVols Vol_Interval VOL1 Vol2 Vol3

______ _______ ________ ____________ _______ _______ _______

NaN NaN NaN NaN NaN NaN NaN

>> disp(Configuration)

T2 = Configuration

W=width(T2)

BookID = 2;

State = ‘Open’;

noofVols = 2;

Vol_Interval = 4;

VOL1 = ‘BX2’;

Vol2 = “not used’;

Vol3 = ‘not used’;

appendRowVars = {BookID, State, noofVols, Vol_Interval, VOL1, Vol2, Vol3}

T2(end+1) = appendRowVars;

I am using MATLAB version 9.5.0.944444 (R2018b),. When I run this I get T2 = 1 x 7, W = 7, then I get an error message "Conversion to double frm cell is not possible"

Help

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Jo Bremer Balestracci 2020-9-29

编辑：Jo Bremer Balestracci 2020-9-29

I want to add a row at the end so that it looks like this:

BookID State noofVols Vol_Interval VOL1 Vol2 Vol3 Workpace would indicate

2 Open 2 4 BX2 not used not used 1x7

4 Closed 3 25 BX1 not used BX5 2 x 7

So everytime I run the code it adds a row to the "Configuration" table

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Answer 1

Image Analyst 2020-9-29

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在 MATLAB Online 中打开

Try this:

% Create initial table, which poster forgot to supply us with:
variableNames = {'BookID', 'State', 'noofVols', 'Vol_Interval', 'VOL1', 'Vol2', 'Vol3'};
numRows = 20;
nanColumn = nan(numRows, 1)
ca = {'Not Used'};
nanStr = repmat(ca, numRows, 1);
Configuration = table(nanColumn, nanStr, nanColumn, nanColumn, nanStr, nanStr, nanStr, 'VariableNames', variableNames)
% Get new varaible values somehow.
BookID = 2;
State = 'Open';
noofVols = 2;
Vol_Interval = 4;
VOL1 = 'BX2';
Vol2 = 'not used';
Vol3 = 'not used';
% Make a table of a single row, from the new variable vaues, 
% that we can append to the Configuration table.
oneRowTable = table(BookID, {State}, noofVols, Vol_Interval, {VOL1}, {Vol2}, {Vol3}, 'VariableNames', variableNames)
% Now we have the table and we can now append a new row.
T2 = [Configuration; oneRowTable]

You'll see

T2 =

21×7 table

BookID State noofVols Vol_Interval VOL1 Vol2 Vol3

______ ____________ ________ ____________ ____________ ____________ ____________

NaN {'Not Used'} NaN NaN {'Not Used'} {'Not Used'} {'Not Used'}

2 {'Open' } 2 4 {'BX2' } {'not used'} {'not used'}

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Jo Bremer Balestracci 2020-9-30

编辑：Jo Bremer Balestracci 2020-9-30

I have tried the fix and it works. But I have twenty (20) variables and it doesn't work. It does work if I limit my variables.

So this "variableNames = {'BookID', 'State', 'noofVols', 'Vol_Interval', 'VOL1', 'Vol2', 'Vol3'};" needed to be expanded to contain 20 variables. I did expanded it to 20 and that is when I got this error:

variableNames = {'BookID', 'State', 'noofVols', 'Vol_Interval', 'VOL1', 'Vol2', 'Vol3', 'Vol4', 'Vol5', 'Vol6', 'Vol7', 'Vol8', 'Vol9', 'Vol10', 'Vol11', 'Vol12' 'Vol13', 'Vol14', 'Vol15’, 'Vol16', 'Vol17', 'Vol18’ };

↑ - this symbol was under Vol16 Error: Unexpected MATLAB expression.

I then removed all of the Variables past Vol15 to see what would happen and I got this error:

variableNames = {'BookID', 'State', 'noofVols', 'Vol_Interval', 'VOL1', 'Vol2', 'Vol3', 'Vol4', 'Vol5', 'Vol6', 'Vol7', 'Vol8', 'Vol9', 'Vol10', 'Vol11', 'Vol12' 'Vol13', 'Vol14', 'Vol15’ }; ↑ -this symbol was now under Vol15

Error: Character vector is not terminated properly.

So I started to eliminate variable Vol15 and it work. This this means I had eighteen (18) variables. Is there a limitations on the number of Variables?

Steven Lord 2020-9-30

在 MATLAB Online 中打开

The quote before Vol15 is the type of quote MATLAB accepts.

The quote after Vol15 is a "smart quote", meaning I suspect you wrote this code in Microsoft Outlook or in Microsoft Word. Replace the "smart quote" with a regular quote in the MATLAB Editor. It looks like your Vol18 have this same problem.

As for adding rows to a table:

load patients
patients = table(LastName,Gender,Age,Height,Weight,Smoker,Systolic,Diastolic);
patients(end, :) % Mr. Hayes
patients(end+1, :) = {'Branson', 'Male', 40, 68, 180, false, 123, 82};
patients(end-1:end, :) % Mr. Hayes and Mr. Branson

Jo Bremer Balestracci 2020-10-1

Thank you. I will double check the quote and try it again using my longer string.

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Answer 2

Stijn Haenen 2020-9-29

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https://ww2.mathworks.cn/matlabcentral/answers/602080-append-a-row-to-a-workspace-table#answer_502489

在 MATLAB Online 中打开

If you have two tables for example:

a=table();
a.Var1(1,1) = 1;
a.Var2(1,1) = 1;
a.Var1(2,1) = 3;
a.Var2(2,1) = 3;
b=table();
b.Var1(1,1) = 2;
b.Var2(1,1) = 2;

you can insert table b into table a with:

c=[a(1,:); b(1,:) ;a(2,:)];

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Jo Bremer Balestracci 2020-9-29

If just using numbers, this works but I have a mixture of numbers and text. So when I subsitute Var2(1,1) = 'Open' I get an error. The error is:

Error using Possible_Fix.m (line 3) - Unable to perform assignment because the size of teh left side is 1-by-1 and the size of the right side is 1b-by-7.

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Append a row to a workspace table

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Append a row to a workspace table

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