Define a new NC_VLEN type in a new NetCDF-4 file. Then, create and write a variable of this type. An NC_VLEN type corresponds to a cell array in MATLAB®.

Create a NetCDF-4 file named myfile.nc.

source = "myfile.nc";
cmode = "NETCDF4";
ncid = netcdf.create(source,cmode);

Define a new NC_VLEN type with the MY_VARIABLE_LENGTH_SAMPLE type name and NC_FLOAT base type.

typeName = "MY_VARIABLE_LENGTH_SAMPLE";
baseType = "NC_FLOAT";
typeid = netcdf.defVlen(ncid,typeName,baseType);

Create a new TIME dimension with the length 3 in the NetCDF file.

dimname = "TIME";
dimlen = 3;
dimid = netcdf.defDim(ncid,dimname,dimlen);

Create a new variable named samples of the NC_VLEN type and with the TIME dimension.

varname = "samples";
varid = netcdf.defVar(ncid,varname,typeid,dimid);

Write the data to the NetCDF variable. The data is a cell array that contains arrays of single values. The NC_FLOAT NetCDF data type corresponds to the single data type in MATLAB.

data = {single([0.1,0.2]),single([2.333,7.94,0.5,0]),single(4.2)};
netcdf.putVar(ncid,varid,data)

Close the NetCDF file.

netcdf.close(ncid)

Display the contents of the NetCDF-4 file. The ncdisp function lists the new NC_VLEN type in the User-Defined Types section and represents it by its base data type (single) inside curly braces. The Datatype of the new samples variable shows the name of the NC_VLEN type, MY_VARIABLE_LENGTH_SAMPLE.

ncdisp(source)

Source:
           /tmp/Bdoc23a_2213998_1184146/tp56fdf280/matlab-ex80861297/myfile.nc
Format:
           netcdf4
User-Defined Types:
           MY_VARIABLE_LENGTH_SAMPLE: {single}
Dimensions:
           TIME = 3
Variables:
    samples
           Size:       3x1
           Dimensions: TIME
           Datatype:   MY_VARIABLE_LENGTH_SAMPLE