why is there no lines in in my plot

clear;

clc;

close all;

%input the filename you want to consider

%filename=input('what is the filename you want to consider \n','s');

folder ="C:\Users\Ajuff\CLionProjects\C++ML\C++MLP1\cmake-build-debug\tempvstime.txt";

%load file into variable data

data = load(folder);

for n=1:length(data)

fprintf('%f %f\n',data(n,1),data(n,2));

x=data(n,1);

y=data(n,2);

plot(x,y,'g')

end

why is there nothing in the plot the fprint f prints out values

Answer 1

[Samhitha]

Hi Alexander,

To visualize data points iteratively and connect them with lines, you can use MATLAB's “hold on” function. This allows you to add new data points to an existing plot without erasing the previous ones. By updating the plot in a loop, you can dynamically visualize how the data evolves over time. Additionally, by using the “plot” function with a line style input, you can connect the data points with lines.

You can modify your code as shown below:

% Load file into variable data 
data = load(folder); 

% Initialize arrays for x and y 
x = []; 
y = []; 
% Open a new figure 
figure; 
hold on; % Retain plots so that new points can be added 

% Iteratively add points and update the plot 

 for n = 1:length(data) 
    % Append new point to data 
    x = [x, data(n, 1)]; 
    y = [y, data(n, 2)]; 
    % Print the values 
    fprintf('%f  %f\n', data(n, 1), data(n, 2)); 
    % Plot the updated line with markers 
    plot(x, y, '-o');
 end 

hold off; % Release the plot hold 

Hope this helps!

For more details, please refer to the following MathWorks Documentation:

https://www.mathworks.com/help/releases/R2024a/matlab/ref/hold.html?s_tid=doc_ta