How Can I Save a Struct Array to a Text File?

I have a struct array. Each field in the struct arrray is a column vector, and the column vectors are of unequal lengths.

s(1).t=[1;2];s(1).x=[10;20];s(2).t=[21;22;23];s(2).x=[100;101;102];

My goal is save the data in s to a text file with the elements of each field in s vertically concatenated. The file should look like this:

>> type file1.txt

t,x
1,10
2,20
21,100
22,101
23,102

I thought that struct2table followed by writetable might give me what I want. But, consistent with its doc page, struct2table doesn't do the vertical concatenation the way I hoped it would:

tbl=struct2table(s)

tbl =

  2×2 table

         t               x      
    ____________    ____________

    [2×1 double]    [2×1 double]
    [3×1 double]    [3×1 double]

At present my solution is as follows:

for ii=1:2,s(ii).t = s(ii).t.'; s(ii).x = s(ii).x.';end
snew.t=[s.t].'; snew.x=[s.x].';
tblnew=struct2table(snew)


tblnew =

  5×2 table

    t      x 
    __    ___

     1     10
     2     20
    21    100
    22    101
    23    102

And then I can witetable(tnew).

After I typed all that up, I did find a better way:

s(1).t=[1;2];s(1).x=[10;20];s(2).t=[21;22;23];s(2).x=[100;101;102];
C=arrayfun(@(x) struct2table(x),s,'UniformOutput',false);
vertcat(C{:})

ans =

  5×2 table

    t      x 
    __    ___

     1     10
     2     20
    21    100
    22    101
    23    102

These two lines aren't too bad, except for the need to create the intermediate variable C. Is there an easier and/or better way to write my original struct array to a text file? If it makes it any easier, I may not need the column headings in the text file.

Comment: According the doc in my release, the result of struct2table for a 1 x 2 struct array input is not defined. But, as shown, it worked fine and returned the same result as for a 2 x 1 struct array input..

Answer 1

[Ameer Hamza]

You can directly create a matrix

M = cell2mat(struct2cell(s(:)).')
writematrix(M, 'filename.txt')