Plot all polyshapes in cell array

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Luis Rosety 2022-5-7

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https://ww2.mathworks.cn/matlabcentral/answers/1714050-plot-all-polyshapes-in-cell-array

评论： Steven Lord 2022-5-8

采纳的回答： Voss

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Hello,

I am learing Matlab and I would like to plot all polyshapes stored in a cell array (D) but avoiding for...end loop.

Each cell contains a 2d vector with each vertex coordinates.

So far I only know to plot it like this

for i=size(D,1)
    plot(D{i}(:,2), D{i}(:,1));
end 

Is there any more concise way to achieve it with a single instruction not using a for...end loop?

Thanks

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Answer 1

Voss 2022-5-7

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You could use cellfun:

cellfun(@(x)plot(x(:,1),x(:,2)),D);

That's more concise, I guess, but it also may be less clear than the loop you already have. And it's not likely to be much different performance-wise.

[In general, cellfun(f,C) runs the function f on each cell of cell array C. In this case, the function is the anonymous function

@(x)plot(x(:,1),x(:,2))

and the cell array is D.]

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Luis Rosety 2022-5-8

编辑：Luis Rosety 2022-5-8

Thanks!

This is what I was looking for: A single command.

Voss 2022-5-8

You're welcome!

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Answer 2

Steven Lord 2022-5-8

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If you've already created them in a cell array you can simply turn that cell array into an array of polyshape objects and plot that array. Or you could start with a polyshape array initially, filling it in as you go.

C = cell(1, 10);

A1 = repmat(polyshape, 1, 10);

for k = 1:10

N = nsidedpoly(1000, 'Center', [2*k 0], 'Radius', 0.75);

C{k} = N; % Create a cell

A1(k) = N; % Fill in an array

end

A = [C{:}]

A =

1×10 polyshape array with properties: Vertices NumRegions NumHoles

plot(A)

axis equal

grid on

A1

A1 =

1×10 polyshape array with properties: Vertices NumRegions NumHoles

figure

plot(A1)

axis equal

grid on

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Luis Rosety 2022-5-8

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This doesn't work in my case.

It throws an error:

Error using horzcat
Dimensions of arrays being concatenated are not consistent.

Steven Lord 2022-5-8

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Ah, I went off the subject of the message. You don't actually have polyshape objects in a cell array, you have coordinate data in the cell array. In that case, a skeleton for the approach I'd use:

% C is the cell array of coordinate data
P = repmat(polyshape, size(C)); % One polyshape per cell in C
for k = 1:numel(C)
    data = C{k};
    P(k) = polyshape(data(:, 2), data(:, 1));     
end
plot(P)