Subscripted assignment between dissimilar structures within a table

I'm trying to populate a table that includes a column of 1x1 structs. First I create the table as follows:

tableSize = [500 10];
varNames = ["Name","LocationName","LLA","SystemType","PlatformType",...
    "Antenna","Rx","Tx","Gain_dBi","AdditionalInfo"];
varTypes = ["string","string","cell","string","string",...
    "string","logical","logical","double","struct"];
rxTable = table('Size',tableSize,'VariableTypes',varTypes,'VariableNames',varNames)
rxTable =

  500×10 table

      Name       LocationName        LLA         SystemType    PlatformType     Antenna      Rx       Tx      Gain_dBi    AdditionalInfo
    _________    ____________    ____________    __________    ____________    _________    _____    _____    ________    ______________

    <missing>     <missing>      {0×0 double}    <missing>      <missing>      <missing>    false    false       0          1×1 struct 


rxTable(1,:).AdditionalInfo
ans = 

  struct with no fields.

Then, after defining all the inputs, I try to populate a row as follows:

additionalInfo  = struct('URL','www.google.com', 'SNR', 10, 'NumElements', 1, 'NumChannels', 1);
rxTable(i,:) = {name, locationName, LLA, systemType, platformType, antenna,...
    Rx, Tx, gain, additionalInfo};

All the variables are successfully populated as expected except the struct in the last column. It gives me the following error

Subscripted assignment between dissimilar structures.

I'm guessing it has to do with trying to replace the initially defined empty 1x1 struct with a populated 1x1 struct, but I can't figure out how to get arround it.

Answer 1

[Stephen23]

A 1x1 structure is not empty, it is scalar: its size is independent of how many fields it has.

You are trying to assign a structure with fields to elements of a structure with different fields (i.e. none). That is not allowed. However you can replace the structure array with one containing the required fields:

T = table('Size',[5,2],'VariableTypes',["double","struct"],'VariableNames',["A","B"])

T = 5×2 table
    A        B     
    _    __________

    0    1×1 struct
    0    1×1 struct
    0    1×1 struct
    0    1×1 struct
    0    1×1 struct

T.B % lets check that the structure has no fields

ans = 5×1 struct array with no fields.

T.B = struct('X',cell(5,1),'Y',cell(5,1)) % <- create all of the fields (but no data!)

T = 5×2 table
    A        B     
    _    __________

    0    1×1 struct
    0    1×1 struct
    0    1×1 struct
    0    1×1 struct
    0    1×1 struct

T(2,:) = {pi,struct('X',9,'Y',8)} % Now the data assignment works without error

T = 5×2 table
      A           B     
    ______    __________

         0    1×1 struct
    3.1416    1×1 struct
         0    1×1 struct
         0    1×1 struct
         0    1×1 struct

T.B(2) % Lets check the structure data for that row

ans = struct with fields:
    X: 9
    Y: 8

[Jordan Wiker]

That makes sense, thanks!