Need help fixing simple function

I have a function that simplifies coordinates and colors

The part that edits the coordinates is correct, but the colors is not

Here is the function

%function positionsnew = CubeLayout(RawCoords, Colors)

%Pre allocates newcoords
newcoords = zeros(9,1);

RawCoords = MrCoords; %JUST HAVE THIS AT THE MOMENT TO TEST 

%This determines the position of the coordinates
for k = 1: size(RawCoords,1)
    if RawCoords(k,1) == 1 && RawCoords(k,2) == 1
                newcoords(k,:) = 1;
            elseif RawCoords(k,1)== 1 && RawCoords(k,2)== 2
                newcoords(k,:) = 2;
            elseif RawCoords(k,1)== 1 && RawCoords(k,2)== 3
                newcoords(k,:) = 3;
            elseif RawCoords(k,1)== 2 && RawCoords(k,2)== 1
                newcoords(k,:) = 4;
            elseif RawCoords(k,1)== 2 && RawCoords(k,2)== 2
                newcoords(k,:) = 5;
            elseif RawCoords(k,1)== 2 && RawCoords(k,2)== 3
                newcoords(k,:) = 6;
            elseif RawCoords(k,1)== 3 && RawCoords(k,2)== 1
                newcoords(k,:) = 7;
            elseif RawCoords(k,1)== 3 && RawCoords(k,2)== 2
                newcoords(k,:) = 8;
            elseif RawCoords(k,1)== 3 && RawCoords(k,2)== 3
                newcoords(k,:) = 9;
    end
end


%Colors second part of function

Colors = MrC; %JUST HAVE THIS AT THE MOMENT TO TEST 

%reshapes position vector and combines newcoords with Color 
positions = ([1 2 3, 4 5 6, 7 8 9]);
positions = reshape(positions,3,3);
ColorLocation = [newcoords,Colors];

%sets the color vector in a new 3x3 matirx 
positionsnew = zeros(3,3);
for i = 1:9
    for j = 1:9
    if ColorLocation(i,1) == j %if colorlocations column 1 row 1 is equal to 1 then,
        positionsnew(positions == i) = ColorLocation(i,2);
    end
    end
end


%end

MrCoords is this

MrCoords =

     1     3
     1     2
     1     1
     2     2
     2     3
     2     1
     3     1
     3     3
     3     2
    

Again, that part of the code is fine, and does not need adjusting, it outputs newcoords, which is a 9x1 matrix

MrC is this

     MrC =

     4
     5
     5
     1
     2
     1
     5
     6
     6

This is what I need done

ColorLocation combines newcoords and colors, this outputs a 9x2 matrix, the left side being a position, and the right side being a color.

I need to put the respective color in the location of the positions matrix, which is a 3x3

for example, positionsnew is the color output of positions and color location

     positions =
     1     4     7
     2     5     8
     3     6     9
     
     ColorLocation =
     3     4
     2     5
     1     5
     5     1
     6     2
     4     1
     7     5
     9     6
     8     6
     
     positionsnew=
     5  1   5
     5  1   6  
     4  2   6

Please let me know if I can clear anything up,

Answer 1

[Anaghaa]

Hi, I went through the function used and found that the issue lies in the for loop of the code. The inner loop (for j = 1:9) is not necessary since each position is already uniquely defined in “ColorLocation(:, 1)”. The line “positionsnew(positions == i) = ColorLocation(i, 2)” misuses “i”, which is the loop index, not the actual position in the grid. This causes a mismatch, as positions contains grid numbers (1 to 9), not indices.

Here is a solution to map the colours correctly:

% Map coordinates to positions using formula: Position = (Row – 1) x 3 + Column
newcoords = (MrCoords(:, 1) - 1) * 3 + MrCoords(:, 2);

• MrCoords(:, 1) - 1: Subtracting 1 shifts the row index to start from 0 (0-based indexing) instead of 1 (MATLAB's 1-based indexing).
• (MrCoords(:, 1) - 1) * 3: Multiplies the adjusted row index by the number of columns (3) in the grid. This gives the starting position for that row within the linear numbering.
• + MrCoords(:, 2): Adds the column index to determine the exact position within the row. Since column numbers (1, 2, 3) directly map to positions within the row, this completes the calculation.

% Combine positions and colors
ColorLocation = [newcoords, MrC];
positions = reshape(1:9, 3, 3);
positionsnew = zeros(3, 3);
% Map colors to positionsnew
for i = 1:size(ColorLocation, 1)
    [row, col] = find(positions == ColorLocation(i, 1));
    positionsnew(row, col) = ColorLocation(i, 2);
end
% Display output
disp(positionsnew);

The corrected code maps colors to the exact grid positions using “positions == ColorLocation(i, 1)” inside the “find” function.

For reference, below is the link for “find” function:

https://www.mathworks.com/help/matlab/ref/find.html