When creating a table, how do I specify the dimensions of a particular variable?

Question

Rafael Cordero 2021-7-11

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回答： Steven Lord 2021-7-11

采纳的回答： Steven Lord

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Hello all,

Lets say Im defining an empty table as so:

my_table = table('Size', [0,7], 'VariableNames', ...
                                        {'name', 'window', 'fs', ...
                                         'x', 'y', 'z', 'mag'}, ...
                                'VariableTypes', ...
                                        {'string', 'double', 'double', ...
                                         'double', 'double', 'double', 'double'});

The variable that I want to put in in 'window' is actually a 1x2 double. But when I set it:

my_table.window(1) = [1 4];

I get the error:

Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-2.

So: how do I specify that my 'window' is actually 1x2?

Many thanks

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Answer 1

Steven Lord 2021-7-11

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my_table = table('Size', [0,7], 'VariableNames', ...
                                        {'name', 'window', 'fs', ...
                                         'x', 'y', 'z', 'mag'}, ...
                                'VariableTypes', ...
                                        {'string', 'double', 'double', ...
                                         'double', 'double', 'double', 'double'});
my_table.window(1, 1:2) = [1 4]
Warning: The assignment added rows to the table, but did not assign values to all of the table's existing variables. Those variables are extended with rows containing default values.
my_table = 1×7 table
      name       window    fs    x    y    z    mag
    _________    ______    __    _    _    _    ___

    <missing>    1    4    0     0    0    0     0 

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Answer 2

Walter Roberson 2021-7-11

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编辑：Walter Roberson 2021-7-11

You cannot do that using that construction technique.

https://www.mathworks.com/matlabcentral/answers/867193-assigning-nested-tables-inside-a-parfor-loop#answer_735323

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Answer 3

Sulaymon Eshkabilov 2021-7-11

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It is better to create a zero matrix and then assign a table variable, e.g.:

Nrows=10; Ncols=8;
A = zeros(10, 8); 
 my_table = array2table(A, 'VariableNames', {'name', 'win1', 'win2', 'fs','x', 'y', 'z', 'mag'});
 %% Assign the values
 my_table.win1(1)=1;
 my_table.win2(1)=4;
 %% Make a new column (var named "window")
 my_table.window=[my_table.win1, my_table.win2];
 my_table.win1=[];
 my_table.win2=[];