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

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Nina Sweeney 2023-10-3

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回答： Nina Sweeney 2023-10-9

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-

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dpb 2023-10-3

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.

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Answer 1

SAI SRUJAN 2023-10-9

在 MATLAB Online 中打开

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 