how can I plot multiple y values for single x value?

I have to plot multiple y values for single x value, but in the plot all the values related to x=x1 appears on the same column. The relative y values are related to the same day (x) but to subsequent times. I would like to plot y values related to the same x in different columns just labeling the first value of x. It is possible? Thank you The graph that i found is the following but i don't know how to solve the problem.

[Chaman Srivastava]

I'm also looking for a similar solution! Commenting to increase the reach.

[KALYAN ACHARJYA]

@Chaman can you more specific please? To plot the data, the lengths of x and y must be the same. If we consider the same x value for all the corresponding y data, the result will be a vertical line (parallel to the y-axis).

[Chaman Srivastava]

@kalyan acharjya Yes indeed it will be a straight line. But my goal is to obtain a regression curve with confidence interval, something like what is shown in the curve attached.

Any leads for this? Thanks

Answer 1

[Setsuna Yuuki.]

you can try creating a vector of ones and multiplying this by your x values, for example:

y = rand(1,15);
xvalue = 3;
x = xvalue*ones(1,length(y));

scatter(x,y,'LineWidth',3);

[Setsuna Yuuki.]

Or

y = rand(1,15);
y2 = rand(1,10);
xvalue = 3;
x = xvalue*ones(1,length(y));
x2 = ones(1,length(y2));
scatter(x,y,'LineWidth',3); hold on;
scatter(x2,y2,'LineWidth',3)
xlim([0 4])
grid on;

[Chaman Srivastava]

Hey Bastian,

Thank you the piece of code. I have tried something like this but plotting a regression using polyfit isn't working. Any leads on that?

[Setsuna Yuuki.]

I tried it this way

clearvars;
x = linspace(0,30);
i = 0; j = 1;
comp = 1:3:length(x);
vectorx = zeros(1,length(x));

%Vector with three same x values 
for n = 1:length(x) 
    vectorx(n) = i;
     if(n == comp(j)) 
        i = i+1;
        j = j+1;
     end
end

x = vectorx;
%Random data
y = 0.2+rand(1,length(vectorx));

p = polyfit(x,y,1); 
f = polyval(p,x); 

figure
plot(x,y,'o',x,f,'-','LineWidth',3) 
legend('data','linear fit') 
grid on;