Operator '-' is not supported for operands of type 'table'

Hello everyone.

I have been trying to substract arrays. but I get an error message "

Operator '-' is not supported for operands of type 'table'

for

Q_dot{i} = (Q{i}(2:end,:) - Q{i}(1:end-1,:))./(Time{i}(2:end)-Time{i}(1:end-1))';

And part of the code is shown below. How the operator can be modified to handle this problem ? Or how should I modifit the data type ?

Q_dot = cell(1,6);
% table2array(Quat_dot);
Omg = cell(1,6);
for i=1:6
    Q_dot{i} = (Q{i}(2:end,:) - Q{i}(1:end-1,:))./(Time{i}(2:end)-Time{i}(1:end-1))';
         
    Omg{i} = zeros(length(Time{i}),3);
    for k=1:length(Time{i})-1
      % Something 
    end   
end

Many thanks

[Jonas]

can you show or append the variables Quat and Time

[HN]

Thank you @Jonas. It is as in below.

Data{i} = readtable(['20220620/xrd_' S_ID{i} '.txt']);
 
    N_data(i) = height(Data{i});    
    Pos{i} = Data{i}(:,4:6);
    Acc{i} = Data{i}(:,8:10);
    Quat{i} = Data{i}(:,11:14);
    Time{i}(j) = hour*3600 + minute*60 + sec;

[Stephen23]

@HN: what do you expect this code to achieve?:

array2table(readtable(..))

[HN]

That function is just useless @Stephen23. I just forgot to remove it. But I am not sure if this stil affects my question.

Answer 1

[Jonas]

try e.g.

(Quat{i}{2:end,:} - Quat{i}{1:end-1,:})./(Time{i}{2:end}-Time{i}{1:end-1})';

instead of

(Quat{i}(2:end,:) - Quat{i}(1:end-1,:))./(Time{i}(2:end)-Time{i}(1:end-1))';

Answer 2

[Campion Loong]

If you are using table and addressing one variable at a time, dot subscripting (i.e. t.VarName(...) ) is often preferrable to braces (i.e. t{...} ). For one the code is more readable.

Also for reference, this doc topic has some examples on doing Calculations on Data in Tables.

Answer 3

[Siddharth Bhutiya]

The error message in the original question was about '-' not being supported on table. Starting R2023a, tables now support arithmetic operations so you could do things like the following.

T1 = table([1;3],[2;4]);
T2 = table([1;2],[3;4]);
T = T1 - T2

T = 2×2 table
    Var1    Var2
    ____    ____

     0       -1 
     1        0 

T = (T1 - T2) ./ 10

T = 2×2 table
    Var1    Var2
    ____    ____

      0     -0.1
    0.1        0

You can read more about this here: Direct Calculations on Tables and Timetables