Best way to create a matrix of points?

32 次查看（过去 30 天）
Richárd Tóth
Richárd Tóth 2019-9-5
评论： Bruno Luong 2019-9-5
Hello
I have a matrix that contains rectangles(squares in this case), for example:
A=[-5 -4.5 1.5 2; -5 -4.5 2 2.5; -5 -4.5 2.5 3; -4.5 -4 1.5 2; -4.5 -4 2 2.5; -4.5 -4 2.5 3];
for i=1:6
rectangle('Position',[A(i,1) A(i,3) 0.5 0.5]);
hold on;
end
hold on;
axis([-10 10 -10 10])
Each row contains ( ) coordinates.
So in this case the result matrix should contain 12 rows, each represents 1 point, like:
-5 1.5
-5 2
-5 2.5
-5 3
-4.5 1.5
-4.5 2
-4.5 2.5
-4.5 3
-4 1.5
-4 2
-4 2.5
-4 3
The rectangles are not guranteed to form another rectangle, a more realistic set of rectangles:
rect.GIF
  1 个评论
Richárd Tóth
Richárd Tóth 2019-9-5
编辑：Richárd Tóth 2019-9-5
I think I will simply iterate through the rectangles and add all 4 of their points to the result matrix, then select unique rows from the result. If you have a more efficient solution, let me know

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Guillaume
Guillaume 2019-9-5
编辑：Guillaume 2019-9-5
A=[-5 -4.5 1.5 2; -5 -4.5 2 2.5; -5 -4.5 2.5 3; -4.5 -4 1.5 2; -4.5 -4 2 2.5; -4.5 -4 2.5 3];
points = unique([A(:, [1, 3]); A(:, [1, 4]); A(:, [2, 3]); A(:, [2, 4])], 'rows')
is the simplest though posibly not the most efficient.
edit: this may be marginally more efficient, though more obscure:
points = unique(reshape(A(:, [1 1 2 2 3 4 3 4])), 'rows')
  3 个评论
显示 1更早的评论
Guillaume
Guillaume 2019-9-5
Oops! How did that happen, should have been:
points = unique(reshape(A(:, [1 1 2 2 3 4 3 4]), [], 2), 'rows')
Bruno Luong
Bruno Luong 2019-9-5
I don't know how A is generated but you might cautious to replace UNIQUE with UNIQUETOL in case two adjacent rectangles do not have the exact match of coordinates due to round-off.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by