Getting data from more than one field in a struct

Probably shouldn't have used a struct like this but wondering if its possible.

I have a struct Data which has a field houses which has field rooms. And I have XDimension , YDimension etc... for each room.

I can get the x dimension of room 1 in house 1 by doing:

ans=Data.Houses(1).Rooms(1).XDimension

How do I get all the XDimension values for all rooms in all houses.

ans=Data.Houses(:).Rooms(:).XDimension

gives error:

Expected one output from a curly brace or dot indexing expression, but there were 4 results.

Is it possible to do this without using a loop?

Cheers,

Steve

[Mario Malic]

It's doable without for loop, but not viable for high number of houses.

[Data.Houses(1).Rooms(:).XDimension; Data.Houses(2).Rooms(:).XDimension]
% output of this is number of houses x number of rooms

Maybe someone else will provide proper/better answer on this question.

Answer 1

[Walter Roberson]

cell2mat(arrayfun(@(HOUSE) [HOUSE.Rooms.XDimension], Data.Houses(:), 'Uniform', 0))

Assuming that XDimension is a scalar, the [] part should become a row vector contained in a cell array, and the (:) on Data.Houses would cause the cells to be arranged in a column. From there cell2mat() should turn it into a numeric matrix with one row per Houses and one column per Rooms ... assuming that every house has the same number of rooms.

If different houses have different number of rooms, you need to define your desired output in a way that you can still distinguish between the different houses. Unless, that is, you do not need to, such as if you need something like the average length of rooms over all houses, in which case you can

cell2mat(arrayfun(@(HOUSE) vertcat(HOUSE.Rooms.XDimension), Data.Houses(:), 'Uniform', 0))