Can you synchronize two or more timetables if each timetable has a different number of rows and columns?

I have 8 csv files with different types of sensor data. 5 of the files have 3 columns (variables) and 3 of the files have 14 columns. The one column that all the files share is UTC Time. Each file has a different number of rows. Is it possible to use timetables and synchronize to create a single table sorted by time that would then be written to a new csv file? What other MATLAB commands/features might be helpful here? Thank you-

[dpb]

The description of synchronize says it "collects the variables from all input timetables, synchronizes them to a common time vector, and returns the result as a single timetable. ... In effect, synchronize horizontally concatenates the variables of [the input timetables] even when they have row times that differ. As a result, synchronize inserts a missing data indicator in [the output timetable wherever there are missing data from one table at an input time]. If [input timetables] have variables with the same names, then synchronize renames them and copies [all] variables into [the output timetable]."

If that's what you want to happen, then "yes".

Otherwise, you may want to look at the various join functions.

Answer 1

[SAI SRUJAN]

Hi Nina Sweeney,

I can understand that you want to synchronize two or more timetables using MATLAB commands/features.

You can follow the below given example.

Suppose there are two timetables that have different rows and columns. "timetable1" consists of 3 rows and 1 column, while "timetable2" has dimensions of 4 rows and 2 columns. If we combine the two timetable arrays using "synchronize",the resulting timetable will encompass six rows and three variables.

dt1 = datetime('today')+(-1:1).';       % 3x1 datetime array
dt2 = datetime('today')+(-1:2).'+ 2;    % 4x1 datetime array

timetable1=timetable(dt1,[1;2;3]);                 % 3x1 timetable
timetable2=timetable(dt2,[4;5;6;7],[8;9;10;11]);   % 4x2 timetable 
TT1=synchronize(timetable1,timetable2)             % 6x3 timetable

TT1 = 6×3 timetable
        dt1        Var1_timetable1    Var1_timetable2    Var2
    ___________    _______________    _______________    ____

    08-Oct-2023            1                NaN          NaN 
    09-Oct-2023            2                NaN          NaN 
    10-Oct-2023            3                  4            8 
    11-Oct-2023          NaN                  5            9 
    12-Oct-2023          NaN                  6           10 
    13-Oct-2023          NaN                  7           11 

You can refer to the similar community questions for your reference.

Combine Timetable's - MATLAB Answers - MATLAB Central (mathworks.com)

Merging data from different matrices with different row numbers by matching date - MATLAB Answers - MATLAB Central (mathworks.com)

You can refer to the below documentation to understand more about "synchronize" function in MATLAB.

Synchronize timetables to common time vector, and resample or aggregate data from input timetables - MATLAB synchronize - MathWorks India

Answer 2

[Nina Sweeney]

I was losing almost half my records when using synchronize. I used outerjoin instead with the "MergeKeys" qualifier and this fixed the issue.