Structure cell (or matrix) in Matlab

Question

I have a structure with fields ID , Coor , Misc , Conn . ID and Misc are doubles, however Coor is a 1x3 vector and Conn is a 1xn vector (where n could theoretically be from 0 to inf).

 Point(x).ID = [x] Point(x).Coordinate = [xPos yPos zPos] Point(x).Misc = [randomDouble] Point(x).Conn = [someVectorOfNumbers] 

I would like this to appear in an array of cells without using a FOR loop.

Output Example:

 'ID xPos yPos zPos Misc Conn' 1 0 0 0 0 '0 1 2' 2 1 1 1 1 '' ... xxxxx '2' 

Note that Point.Conn , its vector of numbers, is converted to a string.

I'm having trouble splitting Point.Coordinate into three elements and converting Point.Conn to a string.

It seems to me that this can be done using struct2Cell, and then change the level of nesting. I'm just not quite sure how to do this.

Answer 1

First, do some example data:

 n = 10; ID = num2cell(randperm(n)'); Coordinate = mat2cell(randn(n, 3), ones(n,1)); Misc = num2cell(randn(n,1)); Conn = arrayfun(@randperm, randperm(n), 'UniformOutput', 0)'; Point = struct('ID', ID, 'Coordinate', Coordinate, 'Misc', Misc, 'Conn', Conn); 

Now check it out:

 >> Point Point = 10x1 struct array with fields: ID Coordinate Misc Conn >> Point(1) ans = ID: 7 Coordinate: [-0.0571 -1.1645 2.4124] Misc: 0.0524 Conn: [3 2 1] 

Now use arrayfun() to scroll arrayfun() elements of the array of the Point structure. We define a generic function x to work with each Point element, formatting the string as you described:

 Point_cell = arrayfun(@(x) [num2cell([x.ID x.Coordinate x.Misc]) num2str(x.Conn)], Point, 'UniformOutput', 0); Point_cell = vertcat(Point_cell{:}) 

Now check the output:

 ans = [ 7] [-0.0571] [-1.1645] [ 2.4124] [ 0.0524] '3 2 1' [ 5] [ 0.2918] [ 0.4948] [ 0.7402] [-1.9539] '1 2' [ 3] [-0.6146] [-1.2158] [ 0.3097] [ 0.5654] '3 4 1 2' [10] [-0.0136] [ 1.5908] [-0.5420] [ 0.0778] [1x25 char] [ 2] [ 0.4121] [ 0.5265] [ 0.1223] [ 0.0807] [1x22 char] [ 1] [-0.9371] [ 0.2648] [ 0.9623] [ 0.7947] '1 2 5 4 3' [ 4] [ 0.8352] [-0.3936] [-0.2540] [ 1.0437] '6 2 3 7 4 1 5' [ 8] [ 1.0945] [-2.1763] [ 1.8918] [ 0.8022] '1' [ 6] [ 0.3212] [-1.1957] [-1.2203] [-0.4688] [1x37 char] [ 9] [ 0.0151] [ 0.3653] [-0.3762] [-0.0466] '3 5 4 2 6 1' 

I can’t say from your question, but if you want all numeric fields to be an array inside one cell, this is a simple setup. Good luck

Answer 2

Here is a slightly different solution using STRUCT2CELL :

 %# build a sample array of structures id = num2cell((1:10)',2); %' coords = num2cell(rand(10,3),2); misc = num2cell(rand(10,1),2); conn = arrayfun(@(n)randi(5,[1 n]), randi([0 6],[10 1]), 'UniformOutput',false); p = struct('ID',id, 'Coordinate',coords, 'Misc',misc, 'Conn',conn); %# convert to cell array h = fieldnames(p)'; %' X = struct2cell(p)'; %' %# split 'coords' field into 3 separate columns h2 = {'xPos' 'yPos' 'zPos'}; X2 = num2cell( cell2mat(X(:,2)) ); %# convert 'conn' field to string X4 = cellfun(@num2str, X(:,4), 'UniformOutput',false); X4 = regexprep(X4, '[ ]+', ' '); %# clean multiple spaces as one %# build final cell array with headers C = [h(1) h2 h(3:4) ; X(:,1) X2 X(:,3) X4] 

Result:

 >> C C = 'ID' 'xPos' 'yPos' 'zPos' 'Misc' 'Conn' [ 1] [0.78556] [ 0.46707] [0.66281] [ 0.46484] '3' [ 2] [0.51338] [ 0.6482] [0.33083] [ 0.76396] '2 1 2 5 1 2' [ 3] [ 0.1776] [0.025228] [0.89849] [ 0.8182] '1 3 1 5' [ 4] [0.39859] [ 0.84221] [0.11816] [ 0.10022] '1 1 2' [ 5] [0.13393] [ 0.55903] [0.98842] [ 0.17812] '3 1 5 2 2 1' [ 6] [0.03089] [ 0.8541] [0.53998] [ 0.35963] '' [ 7] [0.93914] [ 0.34788] [0.70692] [0.056705] '2 1 3 4 4' [ 8] [0.30131] [ 0.44603] [0.99949] [ 0.52189] '1 1 4 5 3' [ 9] [0.29553] [0.054239] [0.28785] [ 0.33585] '1 5 2' [10] [0.33294] [ 0.17711] [0.41452] [ 0.17567] '2' 

where, for example, the second structure was:

 >> p(2) ans = ID: 2 Coordinate: [0.51338 0.6482 0.33083] Misc: 0.76396 Conn: [2 1 2 5 1 2]