Loop to compare values from the table

I try to create to compare data. I have to tables and i need to compare dates (year, month and day). Each data type is in different column. I try to make a loops to compare first years, second month and for last day and if the dates in both tables are the same I want to have value from another column from one of the table (second one). The value that loop find I need in first Table (from table twl column 7). It could happens that in first table dates are repeated but I still need this values repeated.

Can you help me solve this problem?

My code :

for i = 1:nummel(t21) 
           for j = 1:nummel(twl)
    
                if  isequal(t21(i,15), twl(j,1))
                    
                    if  isequal(t21(i,16), twl(j,2))
                     
                     if  isequal(t21(i,17), twl(j,3))
                                    fprintf('Found! \n') 
                            for j
                                fprintf('\r\n %04d' twl(i,7))
                            end
                     end
                    end
                end
           end
          

[dpb]

Yes. Don't try to compare the pieces separately, convert to datetime and then can do logical comparisons to heart's content.

[Izabela Nowaczynska]

I'm a begginer so can you tell me how exactly should I write this code?

I made something like that but it still doesn't work, what is important that i and j aren't the same size

for i = 1:length(twl1)
    for j= 1:length(d)
        if d(j,1)== twl1(i,8)
            dw1(j,1) = twl1(i,7);
        end
        continue
    end
end

[dpb]

You've not really shown what your end objective is nor what your data are, but if you have two tables that contain dates and need to either compare between them or to find dates or ranges of dates in either one or both of them, convert those both to timetables. There are a zillion things available then to ease the problem. The first thing is/will be to convert the yr, mon, day data columns to datetime()

I can't decipher what in the two variables is which variable but see the documentation for datetime and table and timetable for guidance on how to handle such data in general.

Attach a .mat file with the data you have would probably help immesaurably but a clear definition then of the problem to be solved is far better than trying to debug nonworking code... :)

[dpb]

"I can't decipher what in the two variables is which variable..."

Well, going back to the first, I guess I've determined that the one time data are t21(:,15:17) and the other are twl(:,1:3).

So,

dtt21=datetime(t21(:,15:17));      % datetime array for the t21 data
dttwl=datetime(twl(:,1:3));        % ditto for twl

Now

[ia,ib]=ismember(dtt21,dttw1);     % find locations of matching times t21 in tw1
data=tw1(ib,7);                    % the matching locations column 7 data from the second

[Izabela Nowaczynska]

Thank you very much for your answers.