how to make the regression line of lsline function colored

I have 3 scatter plots that are diplayed in the same graph in three different colors. I would like each of them to have a regression line of the same color. I can only get three grey regression line with the lsline command.

[Joris Bockhofer]

My recommendation would be to forget about lsline

and simply calculate the linear regression yourself and plot the result separately with the color of the original plot.

lsline has taken way more time out of my life than it should and i hope this finds anyone having trouble with coloring it.

My approach looks like this:

rng default % For reproducibility

x = 1:10;

y1 = x + randn(1,10);

y2 = 2*x + randn(1,10); % same size as x

figure

ax1 = gca;

hold(ax1, 'on');

xData = [x; x];

yData = [y1;y2];

legendStrArray = string(); % creat a string array to hold label information

for i = 1:numel(xData(:,1))

dataX = [xData(i,:)];

dataY = [yData(i,:)];

pl1 = scatter(ax1, dataX, dataY); % plot original data

colorRGB = pl1.CData; % get color of plot

% Fit a linear model

model = fitlm(dataX, dataY);

% Get the fitted line data

xFit = linspace(min(dataX), max(dataX), 100);

yFit = feval(model, xFit);

h = plot(ax1, xFit, yFit, 'Color', colorRGB); % plot regression with color

% add to legend with end+1 strategy for when you dont want to set up a dedicated counter

legendStrArray(1,end+1) = "Datasheet: " + string(i); % legend for data

legendStrArray(1,end+1) = "Datasheet: " + string(i) + ", Regression"; % legend for it's regression

% otherwise it mess up the number of plots vs the number of legend entries

end

legendStrArray = legendStrArray(1,2:end);% take off the first empty entry from the legend array bc of end+1

legend(ax1,legendStrArray, 'Location', 'best'); % have a working legend

hold(ax1, 'off');

Why complicated when it could be simple (or was it the other way around?) - Hope this saves you the headache!

Answer 1

[Oleg Komarov]

When you add the regression line call it like this:

h = lsline;

set(h(1),'color','r')
set(h(2),...

for more on color specification

Oleg

[Ziyi Zhu]

Tried it on 2019a but doesn't seem to work...

[Honey]

I have a problem. I have loop for my scattres and I want to do the same which Jonas asked. But the color doesn't change and it is the same color of the last one in the loop.

[Joris Bockhofer]

Honestly this should be made way more obvious, i spend way too long just trying to set color because the way in the documentation wasnt working so i had to do : [h1.Color] = deal(color); because it kept giving me assignment errors, and then i had to find out that lsline automatically plots a line for each held scatterplot, so setting the color from inside the same loop as you are plotting the scatterplot doesnt seem possible. you'd have to create a second loop for iterating over the handles.... this is just top notch