Hi, i want to plot two columns of values of data from excel, the graph includes a zero while the excel sheet doesn't. Here is my code and the graph I got vs what I should get

This is my code

clear all;

clc;

% Load data from Excel

data = xlsread('Results_1.xlsx'); % Replace 'Results_1.xlsx' with your file name

% Extract columns from the data

q = data(:, 2); % Assuming q is in the second column

D_q = data(:, 5); % Assuming D_q is in the fifth column

errors = data(:, 6); % Assuming errors in D_q are in the sixth column

% Plot with error bars and colored line

errorbar(q, D_q, errors, 'o', 'MarkerSize', 8, 'MarkerFaceColor', 'b', 'MarkerEdgeColor', 'b');

hold on; % Keep the current graph and add new data to it

plot(q, D_q, 'Color', 'r', 'LineWidth', 2); % Red colored line

% Customize axis labels

xlabel('q', 'FontSize', 14); % Customize the font size

ylabel('D_q', 'FontSize', 14); % Customize the font size

% Set x-axis and y-axis limits to exclude the origin

xlim([-11, 11]); % Adjust the limits according to your data range

ylim([1.5, 4]); % Adjust the limits according to your data range

grid on;

What I got :

What I should get (similar to it):

My Exel sheet

[Mathieu NOE]

please attach your excel file

[Fatima Al Ghurabi]

Here is the Excel file

Answer 1

[Fangjun Jiang]

I think the last data point (un-wanted) is at (0,0). Your data shows it. You can look at the value of q and D_q.

Answer 2

[Mathieu NOE]

hello again

so your arrays contains 0 after row 22 til the end, that's why your plot goes back to the origin point (this was already pointed out by @Fangjun Jiang in his comment above)

you need to remove the invalid data from your plot

the first option is to simply specify which rows you want to plot - here we need row 1 to 21

clear all;
clc;
% Load data from Excel
data = xlsread('Results_1.xlsx'); % Replace 'Results_1.xlsx' with your file name
% Extract columns from the data
rows = (1:21); % define valid rows (non zeros in all columns)
q = data(rows, 2);   % Assuming q is in the second column
D_q = data(rows, 5); % Assuming D_q is in the fifth column
errors = data(rows, 6); % Assuming errors in D_q are in the sixth column
% Plot with error bars and colored line
errorbar(q, D_q, errors, 'o', 'MarkerSize', 8, 'MarkerFaceColor', 'b', 'MarkerEdgeColor', 'b');
hold on; % Keep the current graph and add new data to it
plot(q, D_q, 'Color', 'r', 'LineWidth', 2); % Red colored line
% Customize axis labels
xlabel('q', 'FontSize', 14); % Customize the font size
ylabel('D_q', 'FontSize', 14); % Customize the font size
% Set x-axis and y-axis limits to exclude the origin
xlim([-11, 11]); % Adjust the limits according to your data range
ylim([1.5, 4]); % Adjust the limits according to your data range
grid on;

[Mathieu NOE]

if you don't want to have to manually select which rows you need to plot , you can also use a logical array

here I decide to plot only rows based on non zero values of D_q

clear all;
clc;
% Load data from Excel
data = xlsread('Results_1.xlsx'); % Replace 'Results_1.xlsx' with your file name
% Extract columns from the data
q = data(:, 2);   % Assuming q is in the second column
D_q = data(:, 5); % Assuming D_q is in the fifth column
errors = data(:, 6); % Assuming errors in D_q are in the sixth column

rows = abs(D_q)>0; % select only rows with non zero elements
q = q(rows);   % Assuming q is in the second column
D_q = D_q(rows); % Assuming D_q is in the fifth column
errors = errors(rows); % Assuming errors in D_q are in the sixth column

% Plot with error bars and colored line
errorbar(q, D_q, errors, 'o', 'MarkerSize', 8, 'MarkerFaceColor', 'b', 'MarkerEdgeColor', 'b');
hold on; % Keep the current graph and add new data to it
plot(q, D_q, 'Color', 'r', 'LineWidth', 2); % Red colored line
% Customize axis labels
xlabel('q', 'FontSize', 14); % Customize the font size
ylabel('D_q', 'FontSize', 14); % Customize the font size
% Set x-axis and y-axis limits to exclude the origin
xlim([-11, 11]); % Adjust the limits according to your data range
ylim([1.5, 4]); % Adjust the limits according to your data range
grid on;

[Fatima Al Ghurabi]

Ok! got it.

Thank you so much !!