CODEWITHSUNDEEP
matlabplot
Juliette
Juliette

Reputation: 341

Change the color of part of the signal MATLAB

I have a simple plot as below

enter image description here

I would like to select the signal between 50 to 100 and change the color to red. Here is the code that I wrote

close all
clear all
clc

%%

t=1:200 ;
 y=sin(t);

 figure (1), hold on, plot(t, y); 
 [x1,y1] = ginput(2)


figure(2), hold on, plot(t,y,'b'), plot(t(t>=x1(1)), y(t(t>=x1(1))), 
'r',t(t<=x1(2)), y(t(t<=x1(2))),'b')

but what I receive is logically not correct

enter image description here

I wanted to change the color of samples between 50 to 100 into red. Could you please let me know how I can do it? (I examined

t(x1(1)<t<x1(2)) but it did not work.

Upvotes: 2

Views: 182

Answers (1)

jodag
jodag

Reputation: 22314

Note that y(t(t>=x1(1)) happens to be valid in this case because t=1:200 corresponds to the indices of y.

To solve your problem you just need to find the proper values using logical indexing.

t=1:200;
y=sin(t);

figure (1), hold on, plot(t, y); 
[x1,y1] = ginput(2);

dt = t(2)-t(1);
figure(2), hold on;
rng1 = t < x1(1);
rng2 = (t+dt) >= x1(1) & (t-dt) <= x1(2);
rng3 = t > x1(2);
plot(t(rng1), y(rng1), 'b');
plot(t(rng2), y(rng2), 'r');
plot(t(rng3), y(rng3), 'b');

Edit I realized I potentially left gaps in the plot. Extended the inequalities to correct this.

Upvotes: 4

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