Operator '-' is not supported for operands of type 'table' even with {}

I have to perform this operation in which all entities, namely d12, T1 and T2 are in table format:

d12{i,1} = norm(T1{i,3:end} - T2{i,3:end} );

In other questions the problem was solved using the right brackets but this seems not to be my case..

[David Fletcher]

No idea, the statement works for me with some dummy tables

[Andrea Sbaragli]

for me as well in the command window but not inside a function. And also without a parametric approach with i but through a specific cell.. What can I do?

[Star Strider]

It is impossible for us to correct code we can’t actually work with.

If you copy it as text and paste it as text (not an image) to a Comment here or as an Edit to your original Quesiton, this would likely be a more productive use of your time and ours!

[Andrea Sbaragli]

Yes sure! this is my function. It returns me the error in the bold line.

function [report12,d12] = interactions(T1,T2, j, k, stamp1, stamp2)

%   Variables initialization
T1 = array2table(T1); 
T2 = array2table(T2); 
stamp1 = array2table(stamp1)
stamp2 = array2table(stamp2)
report12 =array2table(zeros(j,4));
d12 = array2table(zeros(size(stamp2)));
i = 1; 
counter = 0; % partial cont sum distances btw tag below the critical threshold
n = 0; % partial cont number of istances
t= 0;
% reshape array size 

T2(1:k-j,:)=[]; %same dim of T1

 for i= 1:height(T1)
t=0; 
d12{i,1} = (norm(T1{i,3:end} - T2{i,3:end} ));

if d12{i,1} <= 2 % critic threshold distance in mtrs for a COVID-19 contact
    counter = d12{i,1}; 
    report12(i,1)= stamp1(i,1)% starting time
    n=n+1
    %t=i+1;
   for t = i+1 :height(T1)
       d12{t,1} = norm(T1{t,3:end} - T2{t,3:end} );
           if d12{t,1} <= 2
                counter = counter + d12{t,1}; 
                n=n+1; 
                t=t+1;
           else
               report12{i,2} = stamp1{t-1,2} % end time
               report12{i,3} = report12{t-1,2} - report12{i,1} % contact duration
               report12{i,3} = counter/n; % mean distance during the contact
               counter = 0; 
               n=0; 
               t = height(T1) + 1; % it allows to exit from the 2nd for cycle
           end    
   end
end 
 i= i+1;
end 
end

[Walter Roberson]

Why are you using tables at all in that code? Why not just use numeric arrays?

I speculate that the T1 or T2 that you pass into the function might already be a table, and when you do array2table you might be wrapping a table inside a table.

[Stephen23]

Quite likely that T1 and/or T2 are not numeric array inputs when the function is called.

What is the complete error message that you get? This means all of the red text.

[Andrea Sbaragli]

Since arrays stamp1 and stamp2 are in datetime format, and in report12 must coexist double and datetime values I decided to switch all inputs to table format because mixing them in arrays does not work. Moreover, before start the function T1 and T2 dimensions are as it follows:

1- T1 = jx4 double

2- T2 = kx4 double

where j and k are, of course, integers

Currently, the error seems solved but I have this one regarding mixing datetime and double in line 24 (report12(i,1)=stamp1(i,1))

The following error occurred converting from datetime to double:

Undefined function 'double' for input arguments of type 'datetime'. To convert from datetimes to numeric, first subtract off a datetime origin, then convert to numeric using the SECONDS,

MINUTES, HOURS, DAYS, or YEARS functions.

Kind of wierd considering that report12 is initialized as a table...