Read netCDFs in loop and export to table with different sizes

I am reading several netCDF files with a datetime and corresponding data.

All datafiles have a different lenght, so I thought to find the common range of datetime for all files and save the corresponding data in 1 table so that I have a table like:

[datetime sensor1 sensor2 sensor3 sensor...]

I already found a way to read the files and find the common date but struggle to get evertyhing into 1 table.

Does anyone has a suggestion?

addpath(genpath('./'))
path = 'F:\Waterlevel/';
netCDF = dir([path,strcat('**/Sensor_*')]);

for i = 1:length(netCDF)
    baseFilename = netCDF(i).name;
    fullFileName = fullfile(path, baseFilename);
    fprintf(1, 'Now reading %s\n', fullFileName);
    nt = ncread(fullFileName, 'datetime');
    Times = datetime(nt, 'convertFrom', 'posixtime', 'Format', 'yyyy-MM-dd HH:mm:ss');
    nlevel = ncread(fullFileName, 'level'); 
    
    [commondates, whereina, whereinb] = intersect(Times,Times(1:length(i)));
    firstcommon = commondates(1);
        
end

Answer 1

[Eric Sofen]

I would suggest using timetable and the synchronize method.

I assume nlevel is the sensor data? If so, build up a cell array of timetables in the loop, then synchronize them.

Edit: fixed concatenation code.

addpath(genpath('./'))
path = 'F:\Waterlevel/';
netCDF = dir([path,'**/Sensor_*']);
alldata = {};
for i = 1:length(netCDF)
    baseFilename = netCDF(i).name;
    fullFileName = fullfile(path, baseFilename);
    fprintf(1, 'Now reading %s\n', fullFileName);
    nt = ncread(fullFileName, 'datetime');
    Times = datetime(nt, 'convertFrom', 'posixtime', 'Format', 'yyyy-MM-dd HH:mm:ss');
    nlevel = ncread(fullFileName, 'level'); 

    alldata = [alldata, {timetable(Times,nlevel)}];
end

finaldata = synchronize(alldata{:},'intersection');

[Eric Sofen]

Also, you don't need the strcat in the dir call.

[Siegmund Nuyts]

Hi Erik, thanks for your suggestion.

Yes, nlevel is the sensor data.

Using your code, I still get an error "All tables being horizontally concatenated must have the same number of rows"...

[Eric Sofen]

Whoops! alldata should be built up as a cell array of tables:

alldata = [alldata, {timetable(Times, nlevel)}];

[Siegmund Nuyts]

That worked perfectly! Thanks a lot