Reshape Nx1 struct with field of Mx1 elements to N*Mx1 vector

I have a struct A of [1000x1] size. There is a field "bar" which has [100x1] elements.

I want to have 1 variable, let's say B, which will be [1000*100x1] of "bar" elements.

How can I do it without iterating a struct and appending on some prepared zeroed vector? Can reshape do it?

[Stephen23]

"How can I do it without iterating a struct and appending on some prepared zeroed vector? Can reshape do it?!

No, but a comma-separated list can do it:

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

Answer 1

[Bruno Luong]

Something like

B = cat(1,A.bar)

Answer 2

[MJFcoNaN]

This is an example:

bar=rand(100,1)

bar = 100×1

0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464

A=struct;
A.bar=bar;
% copy A.bar to all 1000 elements
A(2:1000,1)=A(1)

A = 1000×1 struct array with fields:
    bar

% table is a good intermediate form
tbl=struct2table(A);
B=cell2mat(cellfun(@transpose, tbl.bar, 'UniformOutput', false))

B = 1000×100

0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013 0.4600 0.1687 0.4194 0.2287 0.7427 0.7976 0.8690 0.4868 0.9914 0.4464 0.1298 0.0337 0.5265 0.2551 0.7338 0.6966 0.2969 0.3447 0.0830 0.7853 0.9779 0.2714 0.3507 0.4244 0.3516 0.3386 0.8395 0.6153 0.2840 0.6013

[Sabyrzhan Tasbolatov]

Thanks, I'm going to use cat as it's faster

Elapsed time is 0.001430 seconds.

I've also tried your option, it takes:

Elapsed time is 0.020119 seconds.