MATLAB Answers

0

hi everybody , i have a question please , if i have X=[1:10] and Y=[-5:5] and i want to have all the point of the plane (x,y) , what can i do in matlab to extract this point to use it

Asked by mina massoud on 25 Feb 2019
Latest activity Edited by Jan
on 27 Feb 2019
X=[1:10];
Y=[-5:5];
for i=1:10
for j=1:10

  3 Comments

Please be more clear, what do you want exactly?
I do not understand also, what "have point of the plane" means. Extract them from what?
BY the way: -5:5 is a vector already and you do not need the square brackets. And it has 11 elements, not 10.
first i need to thank you for responding on my question ,
i try now to be more clear
1) what i need is a column vector 2x1 where the first row is x and the second row is y
2) i need to repeat it to get all the point of the plane (x,y)
for example if X=[ 1 2 3 4 5 ]
Y=[ -5 -4 -3 -2 -1 0 1 2 3 4 5]
so (1,-5) (2,-5) (3,-5)(4,-5)(5,-5)
(1,-4) (2,-4) (3,-4)(4,-4)(5,-4)
(1,-3) (2,-3) (3,-3)(4,-3)(5,-3)
and so on till ..........................................(1,5) (2,5) (3,5)(4,5)(5,5)
so i need in a cartesian coordinate all the pointi (x,y) to use it in a certain iteration
so every cycle i need to extract a point (x,y) that is a column vector 2x1 where the first row is the point x and the second row is the point y to use it in a certain iteration
thank u very much

Sign in to comment.

Tags

Products


Release

R2018b

2 Answers

Answer by James Tursa
on 25 Feb 2019
Edited by James Tursa
on 25 Feb 2019
 Accepted Answer

Does this do what you want?
[x,y] = meshgrid(X,Y);
result = [x(:),y(:)];
Then iterate over the rows of result.
Or you can just use your double for loop, and have
for i=1:numel(X)
for j=1:numel(Y)
point = [X(i),Y(j)];
etc.

  6 Comments

i tried this code but it didnt work
clear all
clc
intx=10;
inty=10;
D_x=3000;
D_y=1000;
x=[0:intx:D_x];
y=[-D_y/2:inty:D_y/2];
k=0
TgT=zeros(length(x),length(y))
for i=1:length(x)
for j=1:length(y)
k=k+1
TgT(k,:)=[x(i),y(j)]
end
end
You didn't pre-allocate TgT to the dimensions I specified. You have this:
TgT=zeros(length(x),length(y))
But I have this:
tgt = zeros(numel(x)*numel(y),2);
@mina: "it didnt work" is not useful to explain a problem. Do you get an error message (than post a complete copy) or do the result differ from your expectation (then explain both).
clear all; clc is called "cargo cult programming": It does not help to solve any problem. All it does is to waste processing time here.
A simpler method instead of the loops:
x = 0:intx:D_x; % No need for brackets
y = -D_y/2:inty:D_y/2; % x and y are vectors already
nx = numel(x);
ny = numel(y);
TgT = [replem(x.', ny, 1), repmat(y.', nx, 1)];

Sign in to comment.


Answer by madhan ravi
on 25 Feb 2019

I am not sure I fully understand but see if it does what you want
[x,y]=ndgrid(X,Y);
[x(:) y(:)] % after this it’s just matrix manipulation

  0 Comments

Sign in to comment.