Unable to perform assignment because brace indexing is not supported for variables of this type

Hello Everyone,

Hope you all are doing well.

I have a question for ADAS Programmation.

Where i am trying to create an object using the class file and Initially i have defined the variable name as left line and right lines of the road.

But now i am trying to automate the lines detected and the data populated must be segregated for the simulation purpose.

But i get an error of brace indexing is not supported.

My code is:

IdxLines = numel(simout.logsout.get("<B_x_VS_LaneBoundaries>"). ...
    Values.LaneBoundaries);

for IdxLines = 1:5
    sLineMajor{IdxLines,:} = simout.logsout.get("<B_x_VS_LaneBoundaries>").Values.LaneBoundaries(IdxLines);
    vLineWidth{IdxLines,:} = sLineMajor(IdxLines,:).Width.Data(:);  % Lane boundary Width
    vLineHeadingAngle{IdxLines,:} = sLineMajor(IdxLines,:).HeadingAngle.Data;
    vLineType{IdxLines,:} = sLineMajor(IdxLines,:).BoundaryType.Data(:); % Lane type 1 - Solid, 2 - Dashed
    vLinexpos{IdxLines,:} = sLineMajor(IdxLines,:).Coordinates.Data(:,1,:); % xpos of the line
    vLineypos{IdxLines,:} = sLineMajor(IdxLines,:).Coordinates.Data(:,2,:); % ypos of the line
    vLineQuality{IdxLines,:} = sLineMajor(IdxLines,:).Strength.Data(:); % Represents the Line Quality,

    oLine{IdxLines,:} = roadLines(vLineWidth,10,vLineHeadingAngle, ...
    vLineQuality,vLineType,vLinexpos,vLineypos);

end

Class def file:

classdef roadLines
    % Class for defining line properties

    properties (Access = public)
        Width;             % Width of the Line specified on the simulink file
        viewRange; 
        headingAngle;
        Quality;
        Type;               % Type of Line dashed, double lines, solid, dotted and non continuous
        xPos;               % Y Position of the Line    
        yPos;               % X Position of the Line
        Style;              % Derived based on the type
    end

    methods
        % Constructor
        function obj = roadLines(Width,viewRange, headingAngle, ...
                Quality, vType, xPos, yPos)
            obj.Width = Width;
            obj.viewRange = viewRange;
            obj.headingAngle = headingAngle;
%             obj.curvature = curvature;               % Currently
%             commented out as it is not used anywhere
%             obj.curvatureDerviative = curvatureDerviative;
            obj.Quality = Quality;
            obj.Type = vType;
            obj.xPos = xPos;
            obj.yPos = yPos;
            obj.Style = setStyle(obj);
        end

        function cDisplayStyle = setStyle(lineProperties)

            vType = lineProperties.Type;

            % Initialize the output cell array with nan values
            cDisplayStyle = cell(length(vType), 1);

            % Loop over each time step
            for idx_Time = 1:numel(vType)

                if vType(idx_Time) == 1 % 1= Solid line
                    cDisplayStyle{idx_Time} = '-';
                elseif vType(idx_Time) == 2 % 2 = Dashed line
                    cDisplayStyle{idx_Time} = '--';
                else % Any other line type is affected to "-." style
                    cDisplayStyle{idx_Time}  = '-.';
                end
                
            end

        end % end displayLineStyle

    end
end

I am sorry i cannot provide the data's as it is confidential.

but i can say that the data's inside lane boundaries are in the format of structs and inside it is the format of time series and each time series is specified as a vector of 3 Dimensioned matrix.

So basically my idea is. That my code needs to extract data's in to multiple objects Like Line1, Line2, Line3 and etc. and the object collections must be formed in to a struct.

The Struct formation is already done and object collection is also done but i am just stuck in this automatic indexing incrementation.

and the incrementation of number must occur automatically.

Thank you for all the answers and support in Advance.

If my question is not clear kindly comment and i will try to clarify it.

[VBBV]

The RHS of first line inside the loop returns a scalar structure from which you can extract field data. If you want a vector form as in non-scalar structures, then use regular brackets () instead of { }

Answer 1

[VBBV]

Try the folliowing

 sLineMajor = simout.logsout.get("<B_x_VS_LaneBoundaries>").Values.LaneBoundaries(IdxLines);
 vLineWidth{IdxLines,:} = sLineMajor.Width.Data(:);  % Lane boundary Width
 vLineHeadingAngle{IdxLines,:} = sLineMajor.HeadingAngle.Data;

[VBBV]

Use struct variable name to access the field data inside the struct. Since this line

sLineMajor = simout.logsout.get("<B_x_VS_LaneBoundaries>").Values.LaneBoundaries(IdxLines);

returns a struct with field variables with some data for each iteration insde the loop, however when you want to store the field data from each struct you can opt for brace indexing

[Ram Prasanth]

Hi @VBBV, Thank you for your reply. I tried this but it outputs only the last struct the first 3 is not stored.

Normally it should store all 4 structs and show itself as an object:

sLineMajor = 

  struct with fields:

            Coordinates: [1×1 timeseries]
              Curvature: [1×1 timeseries]
    CurvatureDerivative: [1×1 timeseries]
           HeadingAngle: [1×1 timeseries]
          LateralOffset: [1×1 timeseries]
           BoundaryType: [1×1 timeseries]
               Strength: [1×1 timeseries]
                  Width: [1×1 timeseries]
                 Length: [1×1 timeseries]
                  Space: [1×1 timeseries]

[VBBV]

Since you want code to extract data from struct fields as objects , it's better to use ( ) than { } However, the field data of all structs will be present in remaining variables, pls check vLineWidth ,it will contain data from all 4 structs

sLineMajor(IdxLines) = simout.logsout.get("<B_x_VS_LaneBoundaries>").Values.LaneBoundaries(IdxLines);
vLineWidth{IdxLines,:} = sLineMajor(IdxLines).Width.Data(:)

[Ram Prasanth]

Hi @VBBV,

Thank you for your Help. it works andbelow is the screenshot of the data stored in the cell arrays.

Furthermore i have found much more efficient way to create the object. Below is the code for that. Please provide your advice if it is ok or is there much better way for it.

IdxLines = numel(simout.logsout.get("<B_x_VS_LaneBoundaries>"). ...
    Values.LaneBoundaries);

for IdxLines = 1:IdxLines
    sLineMajor= simout.logsout.get("<B_x_VS_LaneBoundaries>").Values.LaneBoundaries(IdxLines);
    vLineWidth = sLineMajor.Width.Data(:);  % Lane boundary Width
    vLineHeadingAngle = sLineMajor.HeadingAngle.Data;
    vLineType = sLineMajor.BoundaryType.Data(:); % Lane type 1 - Solid, 2 - Dashed
    vLinexpos = sLineMajor.Coordinates.Data(:,1,:); % xpos of the line
    vLineypos = sLineMajor.Coordinates.Data(:,2,:); % ypos of the line
    vLineQuality = sLineMajor.Strength.Data(:); % Represents the Line Quality,

    oLine(IdxLines,:) = roadLines(vLineWidth,10,vLineHeadingAngle, ...
    vLineQuality,vLineType,vLinexpos,vLineypos);
end

Here is how the object is extracted directly.

Thank you.