Mesh grid from 3-column table

I have a table with values extracted from a csv I want to transform into a grid.

Let's use this table as an example

tdata.x = [1;2;1;2];
tdata.y = [3;3;4;4];
tdata.z = randn(4,1);
tdata=struct2table(tdata);
>> tdata
tdata =
  4×3 table
    x    y       z   
    _    _    _______
    1    3    0.53767
    2    3     1.8339
    1    4    -2.2588
    2    4    0.86217

I would like to pivot this into a 2x2 z matrix where rows/columns are given by y and x respectively, something in this direction:

 x 1        2
y                                                                           
3  0.53767  1.8339
4  -2.2588  0.86217

where the first row are the x coordinates, the first columns is the y coordinates and in-between are the corresponding z-values. So that is to say the z-value corresponding to (x,y)=(1,4) is -2.2588.

Note, I am going to use this grid for other things down the road so solutions involving interpolation are not valid, as well the data is guaranteed to be given on a grid.

Answer 1

[Cris LaPierre]

I think you could achieve something like that using sortrows and reshape.

x = [1;2;1;2];
y = [3;3;4;4];
z = randn(4,1);
tdata=table(x,y,z);
tdata = sortrows(tdata,["x","y"])

tdata = 4×3 table
    x    y       z    
    _    _    ________

    1    3     0.28228
    1    4    -0.50085
    2    3       1.437
    2    4    -0.26357

tmat = array2table(reshape(tdata.z,length(unique(tdata.x)),length(unique(tdata.y))),...
    'RowNames',string(unique(tdata.y)),'VariableNames',string(unique(tdata.x)))

tmat = 2×2 table
            1           2    
         ________    ________

    3     0.28228       1.437
    4    -0.50085    -0.26357

Now use can use the variable names and row names to access your data from the table. The syntax you elect to use to access the data will determine your input order.

% (rows,variable)
Zval = tmat{"4","1"}

Zval = -0.5008

% Alternate syntax
Zval = tmat.("1")("4")

Zval = -0.5008