plotting line graph in different colors using while loop

I have a variable called "data" that's a set of data that's 49 rows x 40 columns. time is the first column (data(:,1)) and I want to plot time against the second column of the data (data(:,2)). When the the values in the second column are in certain ranges, I want the line of the line graph to be different colors. I wrote a while/ if else statement to do this, but it's not plotting anything and I'm not sure why. My code is written below. Thank you in advance!

figure

p = 1 %row that's changing (40 rows in all)

w = 2 %sensor/column number

hold on

while p <=size(data,1) %size of column

if data(p,w)<2.65

plot(data(p,1),data(p,2),'g')

elseif data(p,w)>=2.65 & data(p,w)<3.975

plot(data(p,1),data(p,2),'y')

else data(p,w)>=3.975

plot(data(p,1),data(p,2),'r')

end

p = p+1

end

Answer 1

[Star Strider]

This is relatively straightforward to do with scatter, however plot will not work with it.

colrfcn = @(x) (x(:)<2.65).*[0 1 0] + ((x(:)>=2.65) & (x(:)<3.975)).*[1 1 0] + (x(:)>=3.975).*[1 0 0];

x = 0:0.1:24;                                               % Create Data For Plot
y = 4*(sin(2*pi*x/6)+1);                                    % Create Data For Plot

figure
scatter(x, y, 15, colrfcn(y), 'filled')
grid

Experiment to get the results you want.

In theory at least the patch function could plot a multicoloured line, however definig a colormap that corresponds to what you want to do and that will work with patch seems not possible.

[Lauren Yeary]

I didn't think about using a scatter plot - thank you this solved my problem!

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

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