# Plot blocks of points with a specific color

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Tiago Dias on 26 Nov 2018
Answered: Tiago Dias on 28 Nov 2018
Hi,
I got these points and I want to colour every 4 points with a specific color:
x = [ 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5]';
y = [ 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5]';
Point 1:4 yellow, 5:8 blue, 9:12 red, etc, and I want to plot all the 25 entries. the last "block" with just have the row number 25.
I though doing this:
[n,~] = size(x);
block_points = 4;
t_start = 1:block_points:n;
t_end = block_points:block_points:n;
but I got a problem with t_end, only has size 6, while t_start has size 7, due to the last block that only has 1 number.

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Tiago Dias on 28 Nov 2018
I just want to delete que question, solved the problem on my own
madhan ravi on 28 Nov 2018
ok so the effort put in order to help is for nothing? Just leave it open just don‘t accept the answer. Post your solution as an answer and accept it.
Tiago Dias on 28 Nov 2018
First of all, I did not say that your help was for nothing, I appreatiate the time you spend on my question, like I wrote in the last comment I wrote.
I think I should not accept your answer since, it was not what I looking for, I wanted a more automatic procedure, depending on the variables and not the numbers. I was looking for something that could always work, no matter the X and Y provided, and I was able to acomplish that.
Like I said, thanks for your interest in my question, and the effort that you spent on it.

Tiago Dias on 28 Nov 2018
This is what I did to solve my question:
from a generic
X = [1:25]';
Y = [1:25]';
I want to plot each number of "rows" to a specific color
[n,m] = size(X);
rows = 3;
columns = ceil(n/rows);
extra_row = columns * rows;
X(n+1:extra_row) = NaN; Y(n+1:extra_row) = NaN;
X_new = reshape(X,rows,columns); Y_new = reshape(Y,rows,columns);
legenda = sprintfc('Mes %d', 1:columns);
for j = 1:size(X_new,2)
plot(X_new(:,j),Y_new(:,j),'*')
hold on
end

madhan ravi on 26 Nov 2018
Edited: madhan ravi on 26 Nov 2018
EDITED
xx = [ 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5]';
yy = [ 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5]';
x=reshape(xx(1:end-1),4,[]);
y=reshape(yy(1:end-1),4,[]);
s={'-oy','-ob','-or','-og','-om','-oy'};
for i=1:size(x,1)
plot(x(i,:),y(i,:),s{i})
hold on
end
plot(xx(end),yy(end),'ok',...
'markerFaceColor','k')

Tiago Dias on 26 Nov 2018
I understood that, but if my X has 26 elements, i need to handly plot the last 2. if it has 27 i need to handly plot the last 3.
I would prefer, if it is doable, an aprroach that would read the size of X and reshape in function of the number 4, or 3 or 5 or whatever I need.
I would like to do a reshape of x, transform a X of 1xm into a 4xceil(n/4), where n is the number of rows of X.
I would transform a 26x1 matrix into a 4x7 matrix, with the 2 last entries could be NaN values for example.
x(1) x(5) x(9) x(13) x(17) x(21) x(25)
x(2) x(6) x(10) x(14) x(18) x(22) NaN
x(3) x(7) x(11) x(15) x(19) x(23) NaN
x(4) x(8) x(12) x(16) x(20) x(24) NaN
i want the reshape to do this, or someother tool to get this, when i say i need 4 rows and 7 columns, that i can calculate there 2 parameters based on my original x
madhan ravi on 26 Nov 2018
"I would transform a 26x1 matrix into a 4x7 matrix, with the 2 last entries could be NaN values for example."
matrix=[rand(26,1);zeros(2,1)] %this will do what you want just pad the remaining elements with zeros
Tiago Dias on 26 Nov 2018
I am not explaining my self properly, i want it to be automaticly, i created a new topic for this, thanks for your time !